The new Tayda A-3186 mini SPDT fits the pre-drilled hole perfectly. I think the pre-drilled 6 knob is great for Kaleidoscope.
I highly recommend the technique of wedging the pots on the board and putting it in the enclosure and tightening the nuts on the pots before soldering then in with the pre-drilled enclosure. The holes are not overdrilled at all for the pots I am using. I even scraped some paint off on the threads getting them through.