Having the benefit of a guinea~pig motor, I removed a valve spring from the 2.0 in order to yoink the bottom spring plate (they are the same size). In doing so i saw how the valve seal was situated. After three days of agonizing, I now feel confident that the only thing that matters in installing the seals is that the groove on the valve guide and the ring on the seal fit together. There is some space below the seal once installed...about an 1/8th of an inch...and I realised that the bottom of the seal isn't doing anything: it's the fit into grooves that matters.

I also used one of those Lowe's gift cards to buy a steel sleeve from the 'assortments' drawers. I took a valve seal with me to get an exact match, and will use the sleeve to tap down the seal. I now have a better idea as to when to quit tapping.

I'm going to get the head finished tonight, then my next biggie is to replace the oil pump. And then...wonder of wonders...I'll actually start reassembling the engine. Like so many of you guys here, the truck has been out of service for weeks. I'm pretty damned horny to be driving it again.

A side note: since I was ordering from RockAuto, I went ahead and got an input shaft bearing. Someone (I forget who) recommended it for solving transmission noise. I will have it on hand next time I drop the transmission.