On another note, I've read an awful lot about magazines and spring options for the early TZs, to the point that it's all run together. Since you're the resident expert on these, can you tell me definitively what Mec Gar mags I need to order and what model springs will fit?
Tall order, there!
Magazines on the older Tanfoglio Pistols are quite challenging to find and usually expensive when found.
Mec-Gar occasionally makes runs of the pre-series 88 Tanfoglio and pre-B Cz75 Magazines, #MGGT2116B, but I've not seen any in quite awhile.
Elander made a Cz75 Magazine that would work in both pre-B and Cz75B Pistols as well as pre-series 88 Tanfoglio Pistols, but those also seem to be gone.
Back when I had a pre-series 88 Tz75, I used Israeli/IMI made pre-B Cz75 Magazines in it, and if you could find any pre-B Cz75 Magazines, those would be a very good choice.
Another Alternative would be to slightly modify your Tz75's Frame to accept Cz75B Magazines, as shown here:
https://czfirearms.us/index.php?topic=39056.0For Springs, try Wolff Gunsprings:
https://www.gunsprings.com/CZ/75%20Series/cID1/mID16/dID91For Springs Wolff does not have, you will probably have to resort to using Cz75 Springs from Cz-USA.
You could also ask EAA if they still have any Springs for the older Tanfoglio Pistols left.
Good Luck with your Project!