Hearthstone homestead hearth

[nm240]

I’ve done extensive research on this specific job for well over a year and find this whole thing very confusing/ misleading. I acquired a beautiful hearthstone homestead stove and am in love with it.
I’ll be installing in an existing fireplace that had an old heat from heatilator and finally got around to removing that old beast.

I currently have a tile sub hearth with I’m assuming concrete underneath as in the basement it looks as the previous owner formed up and sistered the joists to support the concrete.

I have a small space 1000 sq ft so don’t want the thing to stick halfway out into my living room but seems that might be my only option as I can’t go much lower due to wooden Subfloor.

NOW, my problem is finding a clear directive on what is acceptable for a heart build for this stove.
Manual requires r value of 6.6 under the stove with 4” legs.

My question is, what has anyone who has this stove used to frame their hearths. The manual states non combustibles under the stove so does that mean I can’t use 2x4 to build a frame? Saw someone mention metal studs but doesn’t that conduct heat, I’m confused. Any explanations / help and specifically pictures (visual leaner) help!

My plan initially was
-self leveling concrete firebox and sub hearth
-durock
-2x4 frame
-fill the voids with mineral wool
-plywood? Or more durock, double layer?
-Finally mortar and tile or stone
I’ve yet to finalize what the finish product will be.

Is the idea there can be combustibles “in the hearth” as long as there is non combustibles (durock, mortar) underneath and on top the hearth? Also thought, has anyone used brick to make a frame? My thought with that is that wouldn't really be good for the load transfers of the stove.
The other thing with the taking up the whole room thing, it states only need r value of 2.5 16” in front of the stove so is it acceptable to have a lower kind of step in front of the stove, or maybe I was thinking make a rounded or hexagon type front. Idk I’m reaching the point of paralysis by analysis and want to do right but man, this is a lot.

Thank you to anyone who can contribute!!

As you can see from first photo here, I didn’t have clearance for a hearth therefore the lintel needed to be moved and figured why not rip the old beast out while I was in there…. Started with grinder and sawzall and ended up using a plasma cutter. Here are some pics of my journey so far 😂

 

[begreen]

The Homestead on short legs has one of the highest hearth insulation requirements in the business. It take quite a bit of insulation to meet the R=6.6. The stove is designed to be on a totally non-combustible hearth with the short legs.

Can you post some pictures of the underside of the hearth in the basement? Is there wood underneath or just concrete?