Greenhouse with Earth Battery in Idaho (12' snow/year) Zone 5a -20°F to -15°F

Hello fellow greenhouse enthusiast!
Looking for guidance from veteran greenhouser's.  I live in Donnelly Idaho and am planning my greenhouse.  We get >12' of snow on average and am in Zone 5a -20°F to -15°F.
My plan:
1.  Greenhouse 30' Long x 12' Wide x 12' High.  
2.  Footing:  4' deep footing of brick w/ Styrofoam insulation on inside and outside.
3.  Walls:  N - will be 12' high x 12" thick post/beam/strawbale wall w/ stucco on the outside.  This wall will have vents at the top below the roof controlled automatically.  I plan to use a vapor barrier on the inside before stucco'n it to keep moisture from the bales.
E - will have 3' high partial post/beam/strawbale/stucco along w/ a door and glazing (polycarbonate)
S - will be 3' high above footing w/ window vents for the summer.  This wont be tall enough to shed all my snow but I have a thrower:)
W - will be 3' high partial post/beam/strawbale/stucco along w/ glazing.
4.  Ceiling will be sheets of polycarbonate double insulated panels.  Need to make sure I can find ones that run the entire pitch of the roof... I've heard splicing them long ways is no Bueno!  Advice here?
5.  Heat - I'm designing a climate battery and plan to run a bunch of ~ 35' - 4" tubes length ways thru the greenhouse coming up into a 55 gallon plastic barrels w/ fan attached to the top of intake run to the ceiling.   Two layers of tubes the first at the 4' footing level, covered by 12" dirt then a 2nd layer of tubes (offset) then also covered by ~18" of dirt.   Should I use 3 layers?  I thought about this but then there are too many tubes for my 55 gal barrel to handle.   Intake will be in NW corner, exhaust will be in the S-E corner.  I was also thinking of running some of these thru the elevated grow beds as well but not sure this is needed since heat rises.  Thoughts on heating elevated grow beds?  Most of my beds will be only 8" above grade... the width of whatever wood I use for separation of beds/walking path.
I'm a huge Sauna guy (daily) so I'm building one in the middle of my greenhouse to keep it warm thru the long winter.  I realize this is a big space eater but  I already have more grow space than needed with this size.  Thoughts on using a Sauna in a GH?  I do realize in the summer I will have to vent it out and that maybe an issue...

I dont want to make this post too long so I'll stop here.  I'm still planning so advice is definitely welcome on size, construction, heating, etc.  Please see the pictures to help understand.  I thank you in advance for your help.  Take care & God bless.
Rob

Howdy Robert, Have you checked out some of the other designs here on the forum ? HERE is one I was involved in that might give you some ideas