No exactly. When Martin tested sandwiched radiator performance (effectively what this setup will be) he showed a measurable performance difference running the heat load to the rear radiator first, followed by the front radiator.Loop order shouldn't matter unless you have serious flow issues. Temp difference shouldn't more then a few degrees if that at any point in the loop. Run your loop whatever way works best as long as the pump doesn't run dry it shouldn't matter what order it's in
Its up to OP how he wants it done, but for efficiency sake, this is the best way (especially considering, if you really think about it, you lot changing the loop complexity much at all either way). But to your point, yes, generally a shorter loop is desired to maximize flow rates.