Hotblast 1400

[niceguypmp3]

I have heard lots on here about people not liking the Hotblast series of wood furnaces due to inefficiency. My parents had a Hotblast 1400 for the last 30 years or so and then about 15 years ago upgraded to a newer Hotblast 1400 because the other one was starting to show it's age. Now my wife and I live in the house and we operate the 1400 when it gets really cold (like 0F or below).
What makes these so wood hungry? Two things i noticed between the older 1400 and this newer one is that this one has a spin draft on the ash drawer when the older one didn't and also the auto draft flapper in the main feed door has 2 small holes in it so that even when closed there is always a small amount of air that is introduced whereas the older one's main door's auto draft flapper is solid with no holes whatsoever.
If i covered the two small holes on this one, would that make it more efficient or would it burn way too slow and create even more creasote? Also, i could grind down the nubs on the spin draft knob so that it closes completely but again, would this cause issues?
Another big complaint i've read alot on here about the Hotblasts is that they create tons of creosote. Why is that? If I used it alot more than I do then i might consider getting a new, better furnace but I feel this furnace still has lots of years left at the rate I use it.
Right now with really dry wood and even turned all the way down, i only get 4 hrs or so of good heat at a time. Is there anything I could do to safely increase it's efficiency?
Sorry about all of the questions, and thank you in advance for any responses!

 

[blades]

the op actualy has the the small model that sells in the area of $1200 or about 900 on sale at box stores- They work fine if you can be around to babysit them. Then there are code issues when using as an add on wood furnace. Solid fueled heating appliances have different specs for the duct work clearances than conventional oil gas or electric systems. Becomes an issue if a problem occurs or when selling.

 

[niceguypmp3]

We use a heat pump as primary heat and the wood furnace has it's own ducts into the 1st floor. When I had the heat pump put in, then i had complete new ductwork put in the basement so they dont share ducting anymore. My parents used the wood furnace as primary heat and the way it was hooked into the ducting, hardly no heat was making it through the ducts due to leakage. Last night after lighting it for the night, then it was taking forever to kick on the fans, so i went down and stirred it up and turned the damper a little bit higher so it would open again.
About 10 mins later after the fans had been running for a bit it smelled like hot metal so i ran down to the basement and while the furnace itself wasn't overheating, I have a magnet thermometer stuck on the black front right above the door so it measures the firebox temp and it was clear up to 600. the damper was shut and as i watched, it was slowly cooling back down. I glanced on the back and i had installed an adjustable fan control and it was hovering 140-150 so like i said, it wasn't too hot but it sure heated the house up to 77 fast lol. it seems as if it's hard to control the burn temp sometimes. it's either slow or fast. it's hard to get an in between burn.