For drilling buttons, I ued the same 1-1/8" hole cutting bit as for wood, normal drill speed. I center punched the holes to start, so Ihad a spot for the drill to center on(don't try this with plexi- shatter city). Used some spring clamps to around the edges to hold the lexan against a scrap CP piece I had. I did leave the protective backing on to minimize the risk of incidental scratching casualties
Nothing too unusual to work with
Oh I also used a spade bit for a 3/4"(?) hole, for my start buttons. THat drilled easy, same as the rest.