I had one in a 20 without any issue, unfortunately pass on dino outbreak. Not sure of 2 in that size tank. They’re pretty active or at least mine was. Maybe get 1 and complement with a few nassarius.
I've got 1 strawberry in a 20 long; about 1/3-1/2 of the tank's footprint is not covered by rocks and available. It's kept everything pretty clean and seems to be looking for even more food so I've started supplementing with nori. I have some dwarf ceriths too in the sand but they're definitely not doing much. I bet 1 will be plenty.