cut from outside not inside - and tape over where u going to cut with paper tape (masking tape?) if u want to make it looks clean , use that plastic thing that people use on desk for wires to go thru. put that in ur frameslider holes . i'm doing some reseach which is best frame slider , i found out that hollow ones suck , so does aluminum. heres some pics what i'm talking about.
i'i'm going to do the same thing .




http://cbrworld.net/forums/thread/863.aspx