Good looking rows there MM. I've tried different variants of the "stacking" (gosh I wish someone would invent a machine that you just throw the wood splits in and the thing walks down a path while making a stack) At any rate, the fastest way (and not saying you're looking for the fastest way) I've found is to split at the stack. (Actually, I do everything right at the splitter including bucking the logs) I figured I had to bend over anyway with the bucket full of splits for the bottom rows (in your case the wheel barrow). I just let a pile of splits grow about 2' tall and just sort of place or kick them from the pile right on the rails. Less wood handling which I like.
Everyone does things differently to feed their inner soul.
Agreed, I kind of try many different ways to mix it up. Sometimes split right next to pile, sometimes split and toss in wheel barrow, or side x side. One thing Im not good at is switching gears. When it's dry or frozen I get my rounds to the yard and just focus on that. Getting as much in as I can while conditions are favorable. Then I can really split and stack anytime. (Thats a great picture BTW)