Twin turbo plans

Hey guys, First off, sorry for all of the questions and long post... It's a ways off, but I'm starting to think about a turbo setup for my 70 duster. I will be putting a t56 six speed in over the next few weeks, after that i will be piecing together an efi system. Finally, i would like to install a turbo system within a year or so if all goes well. Because it is a manual i think it would be best to run a twin turbo setup to reduce turbo lag. I think i am basically going to follow Mad Dart's lead to a 'tee' (thanks for making such a detailed thread on your build!!)
A bit of relevant info on the engine:
4" stroke 'Cast Steel' crank, 6.123" forged I-beam rods, 4.040" forged KB pistons (-20.5cc dish), Edelbrock performer rpm heads (63cc combustion chamber), and ARP main studs
I will later be installing ARP head studs with new cam, and head gaskets.

Now my questions: I have been playing with different thicknesses of head gaskets on compression calculators online. currently I have about 9.8:1 compression (0.040" thickness head gasket). I can find a 0.06" thickness head gasket to get me 9.44:1 compression. I also found these solid copper head gaskets that are 0.080"-0.092" thickness which would be 9.1: or lower compression: http://www.scegaskets.com/Shop/Control/MainMenu/fp/tcat/259890/seo/1/sfv/32777/page/2/SFV/32777

Does anyone know if these gaskets are reliable, or recommended for boost/street applications? Does anyone know of any head gaskets that are 0.080" or thicker that would work for a street application?
Finally, i am a little bit concerned about the cast steel crank and the main studs holding up to this power, whats your guess on how much power/boost the lower end can handle safely...id like to get 10psi and/or maybe 650hp at the crank...Thanks for your input!