Ok, here’s the 100% completed case modification.
I have an Antec SLK2600AMB, but I wish I’d gone with a mid-tower.
FrozenCPU.com didn’t ship a gasket with my window kit, so I have a big gaping hole with moderately sharp metal edges right now. But they did send one, which should be here in a couple days. They were skeptical, but happy to send another, and their shipping time is excellent.
Final decision on case mod: Next time I’ll buy a pre-windowed case.