If I put water in the wrong place in my LG it goes right through the bottom. Or when I tipped the whole contraption once (before eggs set!), and the water from the channels got to the part where the bottom ventilation holes were.

I am thinking of marking the water channels somehow so that I can see them better for adding water. Or probably setting up the syringe and tubing method. I actually like the LG, have another on the way, I think the first one was a gift from like sooo many years ago I can't remember! Still works. Just can't find an accurate thermo/hygro setup.
Anyway, I would think that the safest thing is to put the whole thing into a cat litter pan or on a cookie tray or something.
I would not use paint. Acrylic will not be waterproof (? maybe your acrylics are different from mine?) and anything that is waterproof will be toxic at least until fully cured and maybe beyond.
I wonder if you could make a tin foil tray... I may be doing this today for mine.
My youngest cat discovered the incubator last night .. yikes!
Time to strap it down to the table and make sure the lid cannot be opened. Since I'm going through all of that I'm moving it away from the window to help with temperature fluctuations. I thought we were done with the cold nights here but... not so much. Crossing my fingers that last night's exploration didn't end in a cat-tastrophe
Susan (spoiled So. Cal girl)