Just do it. Either that or some old towels or something would do. I used to keep towels under my freshwater tanks, not for the reasoning you are looking bun to catch the water I spill all over the place lol.
In terms of a nem tank, I'd only do it if you're interested in selling them in your shop. If not, then it isn't worth the trouble IMO
. But we both know nems bring good money so it would be worth it from a profit standpoint.