You should be working directly with your dealer of choice on your system design, not relying on random forum users' expertise. There is no 1 "right" way to do a C4 system. There are always many options, and experience is what will tell you which is better in your specific situation.
I suggest, now that you apparently have interviewed a few dealers, is to pick one and sit down with them and hammer out a system design. Sounds like you want to be involved and that's great - but you will get a much better end product if you partner with your dealer, vs expecting them to work magic on equipment you sourced...somewhere...that they had no say in.