Thanks y'all, great advice here.
I did end up getting it to latch by installing it on the bike, right hand applying rear brakes, left hand squeezing the plates together, left foot holding me up and right foot applying gentle forward pressure on the DS pedal. (Kind of an acrobatic act ...) I suppose it works better on the bike than doing it by hand in your lap because chain tension helps align all the parts.
Surprise ending: now my chain is skipping when on either of my two smallest cogs, which I take to mean time for a new cog stack and/or chain rings. I can't tell for sure where the skipping is happening, front or back. I don't see obvious wear (except for a couple teeth on the middle chain ring) but that may just be because I don't have a new cog stack in front of me for comparison. I put the old chain back on and yes the problem goes away so I'm not done yet.
But now it's been five days since my last real ride so today I'm just going to take my old chain as is and hit the road.