Please help, new building design

Hello, I am living in Ukraine and planning to build a studio from scratch. (A brand new building) I haven't started to do construction yet and I am mostly still in the research and permit phase. I do hope to begin building by September. I will use some of the wall and ceiling anatomy designs that I've seen on this site and the SAE site. I would like to share my plans and ask if there is anything obvious that I am forgetting. The budget is $25,000 USD (which, I hope, is plenty for this part of Ukraine) Any opinions about design and construction are welcomed! Here are the details: -The building will be 7.5m X 10.5m X 4m. One tracking room, one control room and a hallway/iso type room. I want "two leaf" walls and ceilings. MASS 1 -The outside (outer leaf) of the building will be made with 2 rows of 10cm wide solid bricks interlocking, making one 20cm leaf.(sealed on both sides) AIR -20cm-30 cm of air between 2 masses MASS 2 -The rooms will be built as "rooms within a room". The inner leaf will be like an inside-out wall with 2 layers of GB (1st layer 9.5mm, 2nd layer 12mm). -The inside-out wall will have steel studs, rock wool, fabric and slats of wood to make helmholtz resonators as seen on this site and SAE. http://www.saecollege.de/reference_material/index.html -No floating floor. -No HVAC (this is Ukraine) There are some AC and heating options that I'm looking into. -I will buy a voltage stabilizer and line conditioner to clean up the power. -windows between the control room and tracking room -no windows to the outside world. Only a door to outside in the hallway. (Very gloomy I know) -the inner walls will have 3-6 degree slants for high frequency diffusion, corner bass traps etc... -I will be recording loud rock bands and I hope to have a fair amount of isolation from the outside world. This isn't a huge issue though because there are no real sound regulations in this city.... Some questions I have: 1.Does the "inside out wall" work with steel studs? Or would I get weird rattling? Wood here is pretty expensive compared to steel and concrete. 2.Would it be better to build all the walls for the rooms with brick? 3.What sort of sound treatment problems should I expect to encounter with making a brick building? 4.Please, do you have any advice or do you require more information from me? -Dmill