Another deep cleaning, a call to the support engineers (which is XYZPrinting's saving grace, BTW), and the bottom rail is done. The keyed supports I designed to attach the walls to the bottom are slightly too large, so I just cut them down for now. I could probably just reprint though with the keys 1mm shorter to fit better.

And, while I am printing the second rail section, a thought occurred to me: I probably should have mirrored the rail model, as one side has a slightly larger gap for a leaf. I hope it's not enough to make everything off-kilter

Lastly: I think the reason my last 5 attempts at printing the rails failed because the infill was too open for such a wide area. Most problems wound up being de-lamination between distinct build layers. I made these last ones 25% and they seem to be holding. Eats thru the filament spool though...