A couple things to consider... You might try setting up the GPU blocks in parallel flow (GPU blocks aren't sensitive to flow like CPU blocks are) which will increase the flow of the entire loop. The rad placing is fine, having them set horizontally can be a pain (when bleeding).
You might consider adding another t-line/valve line, it'll make draining so much easier. Something like this:
Having a reservoir also makes filling a loops loads easier/faster
You might consider adding another t-line/valve line, it'll make draining so much easier. Something like this:
Having a reservoir also makes filling a loops loads easier/faster