I use a Holley carburetor main jet in the return line fitting. Something about 1/16" (.060") in diameter will restrict the flow enough to prevent a serious drop in oil pressure. Be aware that a full-flow filter has such large openings in the filter media that all it strains out are the big chunks, so you won't get very effective filtering. It makes people feel better, though, thinking they're protecting their engine. If you can find a spin-on filter intended for hydraulic fluid, or something similar that screws onto the remote filter adapter and filters down to 2 or 3 microns, use that type of filter instead of the more commonly available full-flow spin-ons. The cost will be more than the canister filter the factory specified, but it's a little more convenient to use a self-contained filter instead of replacing a cartridge.
Jerry
