Got back from holidays, hauled out the injectors (again), had them rebuilt, got new washers/gaskets, and reinstalled them. I still have the 31s on, but it overall seems smoother in the few kms I've put on it since. The big test will be tomorrow, when I pull the trailer again. Last tank of fuel (through the rockies, towing, mind you) averaged 15.5L per 100 kilometers. Abysmal! If I can get back to 10L/100km again, I should quickly recoup my investment in the injectors. And some extra power will definitely be a bonus.

1991 HZJ77, 1999 KZJ90, 1999 UZJ100, 1992 M101CDN2
https://www.thegearheadproject.com/category/jdm-journeys/