That's a good standard design, reference version, from AMD. If you don't plan on over clocking your GPUs, i.e. add voltage/ heat, yes that is a better design for close fitting cards. Case air in to the card, exhaust out the back. Again, case cooling will be a factor. Common sense seems to go a long way in regards to cooling. You seem to be doing extensive research on this, so go with your gut, you'll be fine in the long run. Plus, an extra case fan, if felt needed, is only about $10.