We mount our grill in the built-in rod-holders using Magma's grill hardware for that, but the same mechanism will work in most clamp-on rod-holders.
FWIW, I also attached Magma's adjustable table support hardware -- designed for use with a rod-holder and their bait cleaning or utility tables -- to the bottom of a teak tray... so now we have a folding teak table, a teak tray, and a second teak tray that mounts in a rod-holder... all "matching" (sorta kinda) and we can move all of that around the boat as necessary.
-Chris