This turned out well! I did adjust the crossmembers slightly to have a tighter pressure fit. I printed a few test pieces and landed on a 5.8x5.8mm profile at 90mm long. The included crossmembers were a bit loose and prevented the rack from assembling exactly at 90º (at least, for my print settings!). I assembled fully with a dab of CA glue.

Great design, this will be heavily used! Thanks.