JC,
I’ll look closer when I have more time….At first glance, I’m not sure where your plumbing wall is on the first floor for the family room WC. You’ll want an 8” plumb wall to insulate the drop, unless you don’t mind hearing waterfalls.
Your dimensions should always be in 4’ increments whenever possible because all your sheet goods, dimensional lumber and even floor coverings are standardized with the four foot rule. Even if you move it out two feet to make a four foot incremental step, it’ll be a financial wash because waste will be less. Considering that, and also the HT room size I currently have, I’d suggest you go 16’ wide in the HT room. With your depth, you are probably looking at a screen width of at least 96” inches. My 12’ wide room is about two feet too narrow for my 96” screen for me to position my M80’s where they should really be, and even at 14’, I think I’d be wanting more width. Also, if you go 16’ wide, you could get four seats across.
I could go on and on and write a book on construction recommendations, but will not bore you as I don’t know your experience with the trades. Feel free to PM or email me with specifics and I’ll be happy to assist. I’ve built a thing or two before….
