I plan on using the fuel filter from around an 84 D150 on Vixen. it has the 1/4" orificed return nipple originally designed as a vapor return. I'm just going to use it for a solid fuel return.
There are two or three Wix filters (others make them) with built in orifices. One number is 5/16, the other is 3/8 and yet at least one other that is a 90* design