@NJCJOE posted:For the O gauge I used 5" top of rail to top of rail. It actually worked out to be 5-1/16". I used beer cans to space the shelves. For the standard gauge I did 7-1/4" top of rail to top of rail. I wanted close spacing to help the shelves disappear.
@gunrunnerjohn posted:Mine are spaced 5.625", but based on Joe's statement, I may cut it to 5.25 and squeeze another shelf or two in. I like how Joe's shelves came out, so maybe I was too generous with my spacing.
Thanks to you both, and @Mark Boyce for the info.