Any fitment issues with that, or particular years/options to look for to get the best rad possible if I decide to pull one at a junkyard?

Don't go used. It is not worth your time and money. For about $100 you should be able to find a new radiator and then you do not have to worry about it. With a used unit you are just asking for troubles and those troubles can directly affect that head you are trying to protect.

As for fittament, stick with Trooper. Rodeo/Amigo/Pup may work, but...the Troopers had some different sheetmetal in the front. Just go for a 2 row radiator from 89-91 and call it good. You might have to go with one for a v6 to get the 2 rows, but any place that has them will be able to hook you up.

I've heard good things, but never used, www.radiatorbarn.com

Good Luck,
Michael