I have two FE's and both use roller rockers, the side-oiler/Jessel's & 428 CompCams system. Ironically, the adjustment you need to make is to LIMIT the
oil to the head with an
oil restrictor .090 hole in the center and about an inch long. George Anderson of Gessford Machine sells them ready to go or have your machine shop make them - one per side. Most fella's and I included use a Melling HV pump rather than HP unit.
Oil pressure should be between 30-40 psi at idle and 75-95 wide open. Some will go outside of these parameters but around there you'll be fine. Don't worry about roller rockers in an FE - just reduce the oil to the head!