Shims for peep sights

Guy I just went through Lewis' thread on getting his .54 GMLRH ready for his cow elk season and noted how some of you were using washers as shims under your peep sights (Williams etc) so I thought I'd pass this along.
Sorry I don't have any pics but I'm wintering in FL and all my toys are up in PA.
When my rifles needed a shim I used to use steel plate but found aluminum much easier to work. When I used to fish the great lakes I had downriggers on my boat which attached to an aluminum plate (6"x6"x3/8" thick).
I measure how much of a shim I need and mark the plate leaving some material to work with. BTW 3/8" is perfect for most sight bases. I clamp the plate in a vise on the line using the vise as a guide for my hack saw because we all know how straight a hack saw cuts!
Then I just work on the shim with a file until I get it the way I need it then drill the necessary holes for the screws. After ensuring that everything works I degrease the shim, prime and paint it with flat black to match the sight.

OH BTW: Too bad you didn't get an elk Lewis. I was hoping to see how well that bullet performed.

Just as an afterthought the creedmoor style sight that I have on my Pedersoli 1874 Sharps was also out of line and looking through the aperature it looked like a fine burr but was a reflection from the sides of hole due to it not being aligned properly. But before I made a shim for it I decided to take the sight apart and found that the base of the sight had a spring steel insert with a bend in it that "locked" the sight in place via a shallow groove at its round base. I put the sight into my vise after doing some marking for the proper location and carefully filed another groove into it. Because my groove was so close to the original I had to make mine deeper and hence had to put a higher bend in the spring steel. But after installation it works great and is perfectly aligned 90* to the bore axis.