WHICH SIM IS BEST?

I have started on the build of a 737ng flight deck. First of all what a great site for builders to gain tips and information and most of all inspiration. I have a couple of questions to ask to help me on my way, and I hope someone can help so here goes.

Which flight model is best for a home build? PMDG 737 FS9 or I fly 737 fs9.

Also I am planning on using two computers utilising one to run captain/first officer displays and also the exterior view via a projector. My second pc will run the central engine display but will I be able to also run a FMC off this computer ( obviously it has a twin monitor graphics card)

Many thanks for any help. Cheers Nick