With resoldering the cut traces you should at least be able to play FX games when you have the original Cart inserted. I haven't tried this myself with my Profighter (don't want to fry mine, 'cause I'm sure there's a reason that CCL has cut those traces), but Fat_Mike & ManuLoewe say it works perfectly with their Wildcards. You won't be able to use a FX Cart as Dummy Cart for other FX games, although.
I could scan my 32 MBit memcard, if this might help you with your 24 MBit problem, but I think at least noone on this board has ever tried adding additional RAM to a profighter (very few people still have one nowadays).
btw, do you also have this weird DSP chip on your profighters mainboard? It's just sitting there and does nothing, since I can't play any DSP games at all, but it is the same DSP chip as Mario Kart and Pilotwings use. I'm wondering if the damn thing either is broken or if it is used for something else.
-Matthias