"Is foam recommend under an acrylic tank on a homemade stand?"
Yes !
For the guys that are saying not to put foam on an AGA Tank & Stand, have you seen the crap that has been coming out from AGA & Oceanic lately ..... I was at a LFS this weekend looking for a stand and non, i repeat non of the AGA stands that i took a look at had the tanks sitting perfectly flush on the top . I would not feel safe if I did not have foam. You can put foam under a tank with trim, you just have to make sure you do not have foam under the part that does not have trim as this could crack the bottom sheet of glass from the pressure of the foam