If it makes you feel any better I dove in the deep end and put clears in my Filco (and mine has 104 keys!) a while back and I didn't break anything! (have actually been using it at work, and it hasn't hiccupped on me yet) So it can be done... Now I did have some previous soldering experience from restoring old cars, but this was the first serious work I'd done involving PCBs.
Also, rather than buying a whole set of greens, you could just buy a POS keyboard with clears or blacks and harvest the springs for "ghetto greens" - would likely be much less expensive, although slightly more labor intensive (you'd have to put the heavier springs in your existing Filco switch bodies...