Loop order is mostly irrelevant to be honest with you, the only 'fixed' point is,
its generally accepted to have the pump straight after the res (if pump isn't actually in your res) which you have outlined in both scenarios there anyway,
a lot of people think that having a rad after a block helps cool the water some before hitting the next block,
truth be told,
it takes a certain amount of time for all the liquid in the loop to reach a balance with temps, might be 15 minutes, might be an hour depending on the size/volume of your loop, but once its settled, its settled and you won't find more than a few degrees difference in temps at any point in the loop (insane methods notwithstanding ofc)
build the loop as you see fit, for tidy...