The kinda switch that Buckethead uses is a momentary 'switch'- it doesn't latch, so it'll pop out when his finger isn't on it. You wouldn't be able to get the same effect using a push/pull pot switch, but i don't think this fella wants that anyway,
I think (not 100% though), that a push/pull switch on a pot is a DPDT switch, so take the hot wire from the output jack, and solder it to one of the corner connections on the switch (marked with a *), then take the middle connection(the #) and connect that to the output jack where the old wire was:
- -
- - unconnected push/pull
- -
* -
# - connected up
- -
If that makes sense :)