Hi all 
I have heard of people using 'viewing cards' to check out composition prior to setting up their LF cameras. I found this handy device at B&H but being the cheapskate that I am, there's no way I'm going to shell out the $$ for it.
My question is, if one wanted to make one of these gadgets, should the viewing hole be cut to 4x5 or smaller? Perhaps 2x2.5? And what if I wanted to add a string for my range of lenses: 150mm, 210mm, & 300mm?
Thanks in advance!

I have heard of people using 'viewing cards' to check out composition prior to setting up their LF cameras. I found this handy device at B&H but being the cheapskate that I am, there's no way I'm going to shell out the $$ for it.
My question is, if one wanted to make one of these gadgets, should the viewing hole be cut to 4x5 or smaller? Perhaps 2x2.5? And what if I wanted to add a string for my range of lenses: 150mm, 210mm, & 300mm?
Thanks in advance!