new tank, protein skimmer location

Hi all my first post.

Ive just bought a new 100L/20g tank and want to do a fowlr setup.

After reading a lot about protein skimmers is the way forward with live rock in the tank, could a have a small sump tank around 10 inch square with no baffles in it and only use it only for the protein skimmer and heater.

I was thinking of drilling the tank for the overflow because there is no way of having a syphon box on due the tank having a seal lid around the edges.

Will this set up work having a sump just for the protein skimmer or is there another thing I could do, before I drill my new tank for no reason.

Thanks all, sorry if it abit of a noob question