I didn't have much else going on tonight, so I got out the parts for the crotch strap anchor kit. Step one is making cutouts in the seat pans to let the belt pass through, although it turns out that this is already done for you. Unfortunately my Hooker rotary buckles are way too big to fit through there, so I'll have to enlarge these holes once I get a better idea of how everything lines up.
The big surprise was that the metal tab on the end of the crotch strap doesn't seem to be the right length. If you put the bolt where it's supposed to go, the thick part of the webbing where it loops around the metal tab is down between the two anchor brackets. This will push them apart by about 3/8", which will cause the alignment of the upper part to be all out of whack. Hmm.
I sent an email to Hooker to see if they have any suggestions. I suspect they might have a different style of strap with a longer attach tab, which would solve my problems.
P.S. I just realized this site is probably now the top-ranked Google search result for "hooker crotch". Great.