Wanted to give an update.
Went ahead with the repair (I've heard mostly bad things about those leak-seal products and then my neighbor tried it and it cost him out the wazoo.)
About four hours after work to disassemble the engine compartment side of things, remove dash, steering-column frame and free the heater/AC unit.
I couldn't access the TIS documents on opening the heater/AC unit (links in PDF mentioned above are dead), so spent the better part of 4 hours opening it up and replacing the evaporator today.
I bought a Behr brand evaporator which looked identical, but doesn't have the foam gasket around the ends or across the top. A trip to home depot for some similarly sized foam gasket material that I hope will hold up...
I also bought a Behr drier/evaporator unit but it arrived with the caps loose in the box (open to air) so I ended up sending it back as I have no way of knowing how long it was open like that.
Managed to put the steering column frame back in today as well and sorted out and re-attaching the wire harnesses where they were zip-tied to the frame. re-attached the engine side hoses and re-filled the coolant and starting pumping vacuum - got to 360 microns after an hour or so (with a small pump), and did a 1-hour vacuum leak test - only rose to 410 microns. Will pump it some more before charging.
The dash should go back in tomorrow.
