OK, Here's my simple solution/Tip/Trick, for the Bare Metal.......get a piece on, wider than you need; get it down, burnish......get a hunk of 3m vinyl tape, ( or similar) I use 1/8 ....Now place the tape on the line; where the bare metal is to be cut.....using a sharp/new blade.....make your slice.....The tape acts as a perfect guide.....and the bonus is....when you pull the tape up.....it will pull the excess Bare Metal with it; leaving you the Exact thickness required......this technique is perfect for those models which have a trim line, that may not be defined great & would otherwise be difficult to have as a straight line to follow for the cutting process.- Good Luck....And by the way....Those models of yours, are a great start !! - Hats off to you !!!