Picked up a Fisher Stove

Welcome to the Forum,
Yes it's a Grandma and built '78 or '79. The trees on a Grandpa are much farther apart at the center door seam. Before '78 it would have straight handles, old style stainless springs and 4 fin draft caps. The flat doors were dropped for 1980.
I wouldn't be concerned with heat output difference between Grandma and Grandpa. You can reduce (and should) to a 6 inch chimney if codes are not an issue in garage and add a baffle raising the output above a stock Grandpa with 8 inch chimney. Log length and burn time are a bit shorter with Grandma since it holds a little less.It very well could have had Forrest paint which is now Stove Bright. You want Satin Black for original finish. The brushed on finish was much earlier stoves before the double doors existed.
I fold rear seats ahead (they flip out of the way and since then, I've removed rear seats since more stoves ride in it than passengers) and lay them on their back in my Land Rover Discovery. Two 2 X 6 planks strapped to bumper prevents them from moving while I "walk" them up.

In 1977 the addition of an upper set of bricks was optional and not all stoves had them. Many single door stoves did, but it's not common to find the second course on a double door. They didn't warp sides without them, or discolor paint on the sides, so they were not necessary to prevent damage. I'm sure raising the firebox temperature was the main reason for them. With the single course around bottom, the baffle is very easy by setting bricks on their edges on the brick retainers. If you want to keep your second course, it would need legs to support the front. I would consider removing upper course for baffle.
The baffle plate size is sized for chimney, not the stove. Connecting to a very large flue would not allow a baffle at all. A 6 inch insulated flue needs the least amount of heat and can be baffled to the maximum size which gives the same amount of smoke space square inch area as flue diameter. (exhaust flow area)
Make a cardboard template to set in place and adjust smoke space to your chimney requirement. We need to know chimney specifics to give you that.

The reason I never give exact baffle plate dimensions across the stove is due to different fabricators making them a bit different.
I notice you have the wider type that he bricks fit across back INSIDE the side bricks. Normally the stove width allows the 5 bricks to fit tight across the stove back when placed in the stove first. The side bricks cover the rear to hold them tight. Notice the exposed steel face plate on the front of yours between doors and angle iron corners. A regular size Grandma made to prints has the doors almost touch the angle iron shown below. I don't have a name for these "wide body" or "Dunn" stoves, but I know the Dunn Brothers (Virginia and W. Virginia) made them this way, and when the door hinge plates were welded to the angle iron as they should be, they made longer bent hinge plates to reach the door.

I can't give baffle plate depth (front to back) since that changes due to plate angle and is adjusted for smoke space needed for chimney size.

Normal width Grandma face and brick fitment; (This Grandma would have 25 1/2 wide top plate made to drawing specs.)
Doors are the same size, notice how much wider your stove body is.

Then figure a 6 inch not 8 and if it's insulated metal it can have the minimum 28.26 square inch area. If you build masonry without insulated flue allow a larger smoke space for more heat to be lost up chimney. Adjusting the baffle is like tuning the stove to the chimney like tuning fuel on carb or fuel injection to the engine. Setting is completely different from a 6 cyl. to an 8 cyl. much like the smaller or larger chimney. The chimney is the engine that drives the stove and has different fuel (heat) requirements. It is much more important than the stove itself.

Square inch area of 8 inch outlet is 50.24 square inches. (radius squared X pi OR 4 X 4 = 16 x 3.14 = 50.24)
The circumference of 8 inch round is 25.13 so 2 inches high is double that or 50.26 square inch opening, which is more than the internal square inch area of outlet, so it is acceptable.
If you go with insulated 6 inch, the minimum square inch area is down to 3 X 3 = 9 X 3.14 = 28.26 square inch opening. That is just over 1 inch opening under the 8 inch outlet minimum.
It won't be angled as much as it should be, so angle it as much as you can.

This is a baffle plate in a 6 inch Honey Bear. The opening area is calculated the same way making sure square inch opening is not smaller than outlet square inch opening.



This type baffle was used on smaller stoves to prevent taking up loading space. It does not roll the smoke back down into flames or direct heat to front as much as the smoke shelf type that is preferable. But you can see how the opening is measured in square inches as not to impede flow.

28.26 is the square inch opening of 6 inch round. (6 inch square would be 6 X 6 =36 square inches) Multiply by height and yes, it would give you cubic inches inside flue. Cubic inch is used for volume, that's not what we're calculating. We're only calculating the square inch opening of space the smoke travels through.
Using a 6 inch flue, you can't make the opening any smaller than 28.26 square inches in any shape. (which is the square inches in a 6 inch circle)
The round 8 inch outlet inside has a circumference of 25.13 inches (the distance around) So a 1 inch high space all around the 8 inch pipe has 25.13 square inches of open space. (not quite as much open space as the inside of 6 inch pipe) Another 1/4 inch larger opening gives you the required 28.26 square inch opening. I didn't do the exact math but 1 1/4 inch gives you over 30 square inches for the exhaust to travel through all around the 8 inch pipe.

Now you've got it.
2 light coats, 2 cans.
No paint inside.
Most Hearth shops have it or google "buy satin black stove bright paint" This is one of the results; Good price with shipping.
http://www.amazon.com/Forrest-Paint-1990-Stove-Bright/dp/B000VYGUTU

Paint it outside with mask and fire outside for final cure. It is the nastiest smelling paint, but good stuff.

Sawzall with lots of oil , run slow to keep blade cool and it shouldn't take long.