when I added the 25 uf bypass cap with the switch I used a 25uf 50 volt

[catnine]

in parallel with a 2uf 25 volt cap . does that really matter what the voltage diff is?

[PRR]

Both caps have to be rated over 3V (for preamp stages).

Higher voltage rating costs more.

However in these values a 3V cap may be too small to handle (or be worth making). 25V and 50V are entirely fine if you can afford the cost and size.