RF distribution block: wire size?

Hey you guys, Just picked up a rockford fosgate dual amp wiring kit (CP4DCKS), and it includes a fused distribution block, and it looks like it has one 4AWG input and two 8AWG outputs, because the two output terminals have a smaller diameter than the input, and I'm pretty sure that that's what the dude I bought it from at best buy said too. My problem is that one of my amps, infinity ref611a, recommends using a minimum 6AWG, so I was planning on running 4AWG all the way to it. I went to a few best buy's and circuit city's, and the consensus among most of them seems to be that if you use 8AWG from the D-block to the amp and keep it as short as possible, it shouldn't be a problem. What do you guys think? Also, what fuse sizes should I use on the D-block?

I agree if you keep it  short it shouldn't be a problem.

stevdart thanks man, I think I understand what you mean. anywhwere between 100 and the total fuse rating of the amp should be safe. One more thing: I have 4AWG from the D-block to the battery terminal, so what would be a good fuse size for that one?