I've always used garden shears. With a dremel I had trouble getting a good angle on the cuts. You should have seen the guy's face at lowes when I asked for something that could cut through bone nice and easy
found some discs and plugs at petland but still not EXACTLY sure where to cut or which is the best way to mount it. I have tried doing research on it but I have not been lucky on finding any sites with good info. I am however gonna chop up my galaxia over the next few days.
For torch corals, I usually just make short cups out of PVC and use them to hold the frags until I can get rid of them. When I mount them on live rock, I drill a hole in the rock just wide enough for the branch to fit into and put a ball of epoxy in there before inserting the branch. Some live tissue does live in the branch so cut as low as you can.