The Speedex 1622 is now at my house (parked in the driveway, can’t get in the shed in the dark, plus it needs rearranged so there’s room). Got it running today and brought it back on a rental trailer.
Wasn’t too bad to get going either - wired in the new ignition coil (bypassing the bad ignition switch), used a random plug wire for a smallblock chevy (now it’s working, I’ll shorten so it fits well), but still no spark - meter looked like the points weren’t opening and closing, so I checked, and they definitely were. Out came the emery cloth, and with a little more tweaking, it coughed and sputtered to life!
I fed it some carb cleaner and seafoam (including some in the gas tank), it blew lots of smoke, etc. Once it ran for a while it smoothed out. Hydraulics work (which is good since they control mower deck height), hydrostatic drive works well in both ranges, both directions, etc. I think the charging system was even working! Might grab some picture tomorrow when I put it in the shed.