Writing/recording studio Build NSW

Hello everyone and John, I've been following this page for a number of years, and observing/learning silently. I'll get straight to the point about this studio, after I quickly explaining our music scenario. We basically write/record with most main stream Australian POP artists, and occasional international artist when they are in town. We have been working out of a number of studios for over a year, and before that was working out of a studio that closed down. We recently got a large warehouse space in which we are planning to build our own facility. When I start talking about rooms it might get a little confusing, so I'll make it clear, plan is to build two identical control rooms, each with a vocal booth. We want to be able to record good vocals that can be sent of to be mixed for radio. We would like the control room sections to sound good enough so mixes can be done, (so the rooms cant sound terrible),... though the primary purpose is to record a decent vocal and to comfortably fit up to 5 people in the control room to write in. Basically we want 2 glorified writing rooms!! We work 90% from logic and occasionally use some rack synths that we have lying around. Basic setup per room consists of a Mac computer, 49 key Midi controller, about 5 racks (pre's and synth modules) and and 2-3 sets of near field monitors per room, all eventually sitting on an Argosy Dual 15K 800 desk. So we don't have any massive analogue desks that we are trying to fit in. The outer dimensions per room should be 3000mm wide and up to 7000mm long (the length can be shortened to get the ratios right) and about 2400mm-2700mm ceiling height. We basically want it to look like 2 big rectangle rooms from the outside,.. well essentially when its done it will look like one big rectangular shaped room with 2 separate work spaces. Here is a rough sketch, the overall warehouse is much bigger, I just drew this to give a visual of the building/construction space. Each pink shaded area is where each set of control room and vocal booth will be. We want each vocal booth to be approx 1500mmx 3000mm and the rest of the space can be shaped into the control room. Plan on having the 2 entrance doors on the left side of the sketch (on the walls that will eventually sit parallel to the 3000 mm dimension text). Idea for each room is basically step into the control room when you go in through the first door, and its vocal booth to be with in that. Not too concerned about noise spill between the each control room and it's booth. Though,. We would like the two sets of rooms to be isolated from each other to somewhat degree, enough that we can have 2 sessions running at moderate levels at the same time without annoying one another. Our rough plans/idea is to have each pair of rooms (control & booth) to be on its own "floating floor", so the 2 pink shaded areas will be two separate floors. Budget for the materials for the whole project (so both sets of rooms) is about $10,000 -$15 000, so hoping that to cover the gyp rock, framing (pine or steel), insulation, doors, electrical (some power points and lights) etc. All labour is free as we have some people including myself who can pull it off. We did a rough estimate, using prices we 'googled' and seems like for aprox $13 000 we can have everything including wood laminate floor and 2 small air-condition units as well. Design we want is something similar but slightly larger than Johns Small studio design TIMES 2 We are leaning towards building with the steel stud wall framing, that seems to be popular. Weight is not exactly a concern, but would be great if we keep it down as we are 1floor up. What do you guys think the best approach should be? we need some design ideas, some advice on where we should go for materials, Some specifics like what insulation to use etc also let me know if there is something that we have missed, we probably have.. Thank you.