I hope it works out well for you.

My only doubt with a lot of the spring repairs I see is that they often get patched with metals/materials that are too rigid and not springy, thus putting more stress on other springs in the seat.

I repaired a seat bottom a couple of years back (haven't used it yet - part of a long term project), but I clamped and wired new springs and repair pieces (cut from identically-shaped springs) in place. In theory, this should allow the springs to flex as intended.

In theory... I'll find out when I can actually drive the car. Again, I hope this works well for you.