I'm doing the same thing in a big concrete building. How much of a difference do those drum shields make? I am making a little computer, mixing, and monitoring booth, and soundproofing the heck out of it so headphone work and playback will be easy, and I might make some sort of drum shield too. But otherwise I'm gonna have instruments and stuff everywhere and stick studio foam everywhere, and make some soundcatchers until I get a ceiling dropped in, right now all there is is rafters. They work fairly well for my purpose - which is to reduce the leakage from other instruments (I like to track a whole band at once) and room reflections in the drum mics. Just FYI my room is set up as "live end/dead end" which allows a lot of flexibility in natural ambiance according to where I set up the instruments. Scott