Mmm, should be able to, at least somewhat.. I think those are just dadoed-in at those 3rd-spaces, but.. you should be able to slot different spacing.. Here's moar info: http://www.roadcasesusa.com/led-par-...l-other-sizes/
re: Casters? No, I ordered w/o, but.. can easily be added..
PS - Ketchinup, Sire..ttys..
j