Why do you want to use a GeForce and a Voodoo 3 on a SS7?
I mean, sure, the GeForce will be faster in some games that can take advantage of Hardware Transform (not Lighting, those games are way too new for this platform) and it's also a lot faster at higher resolutions. I myself usually prefer the GeForce 2 MX for SS7 builds, however, a Voodoo 3 is more than enough for such a slow platform (not to mention its compatibility with all those nice Glide games). I would just go with one of the cards and be done with it.
If you lean more towards later Direct3D / OpenGL compatible games, the GeForce should be fine - hopefully you are not using anything newer than a GeForce 3 (Ti 200/500), because driver overhead will kill performance on SS7.
If, on the other hand, you want to play older Glide games and/or you are fine with lower resolutions @ 16 bit (pseudo-22bit) color, the Voodoo 3 is the way to go.
Another possibility would be to go with a GeForce + Voodoo 2 card, since the switch is seamless (however, this is usually my choice for faster platforms, not SS7).
Keep in mind that many SS7 boards have bad / underpowered AGP implementations, so choose the card carefully (a GeForce 2 MX is a safe bet, for sure, however a GeForce 3 might actually kill some SS7 lower quality boards).
1 x PLCC-68 / 2 x PGA132 / 5 x Skt 3 / 9 x Skt 7 / 12 x SS7 / 1 x Skt 8 / 14 x Slot 1 / 5 x Slot A
5 x Skt 370 / 8 x Skt A / 2 x Skt 478 / 2 x Skt 754 / 3 x Skt 939 / 7 x LGA775 / 1 x LGA1155
Current PC: Ryzen 7 5800X3D
Backup PC: Core i7 7700k