I think you're overthinking it. Just pull the wort for the reduction from where it's easiest for youDoes it matter when you pull the wort for reduction? I usually batch sparge (been too lazy/busy to finish my fly sparge ring), meaning the first runnings will be the highest gravity, ergo shortest route to syrup. I typically batch sparge to make up volume. No point in leaving anything in the grains I don't have to, and plain water for volume is going to affect target gravity more. Is it better to homogenize the 1st, 2nd, and 3rd runnings before drawing the reduction volume? Now I got a new term (Maillard reactions) to go read about. I'd have flunked HomeBrewing 101 a long time ago because of my poor study habits. Not sure I can get this one in before end of the year, at least not fermented and conditioned enough to drink.
Might have to drink Q4-22 beer in Q1-23 if I decide to give this a go. Looks and sounds yummy.
I biab, so it's all 1st running for me