Greg Elmassian said:
typical household acrylic latex should not attack the foam.
On the crossovers, you have plenty of room to use longer switches, since you have some straight track adjacent.
The track to track spacing using the Piko R7 switches for your crossovers may work… you might have to trim them a bit. I have crossovers between my 2 mains with Aristo #6 and the track to track spacing is about 9.5"
I’ll break anyrail out tonight and see what I can come up with, if I do an update to it, I’ll post it here.