I cut all my bulkhead holes, through 3/4" acrylic. I used a hand drill with a 90 degree hand grip attachment, along with a portable drill press device I got from Home Depot. The drill press holds the drill in place and slides on two metal rails up and down, has a hard plastic foot that lays flat on the acrylic and allows the hole saw to slowly make contact without kicking back or sideways. Make sure you get the right hole saw that has the low profile teeth and not the aggressive ones for wood. Go slow, heat is your enemy, stop often and let the acrylic cool down, use water if necessary to keep the acrylic cool. I just went really slow, it was very easy to do. I did mess up one hole before I got the drill press so I had to go bigger and get a bigger bulkhead to cover up my mistake. As long as you go slow, use the portable drill press and use the correct hole saw you will not have a problem.
almost forgot, I also layed down 1/4" plywood, taped it down with duct tape and drilled through the wood then the acrylic, it prevents movement when starting the hole in the acrylic and allows a nice clean cut
