Don't use water to wet mount. It's very likely you will damage the negatives. Water softens the gelatin so the negative is very fragile when wet.

Kami is easy to use, and there is tape available that doesn't dissolve in Kami. I imagine the tape will also work fine with your homebrew mounting solution based on naphtha. Make sure you use a mylar cover sheet and don't just tape the negative down.

I only use wet mounting for scanning. For enlarging I find it easier to print dry between two pieces of glass. It takes less time to remove the dust than to wet mount and clean up afterwards.