Datsun Roadster Forum-311s.org

You want about a 3/8 inch bead laid down on brake kleened metal which will bead on inside and out side , let dry 24 hours , I would sand the block to clean metal .
it works better with a bump that holds the pan from squishing the rtv down to a film ( most manufacturers went to this ) I've seen lock washers on the bolts between both used to keep the pan slightly off the block
If it's put on thin the oil does work to destroy the bond to metal then the compression will blow out the seal last way longer with the squished out design

You can use Toyota FIPG/Ultra black with or without a gasket.

In many applications, (transmissions, pumps etc), the gaskets are part of the “stack” and affect other important clearances/end play/dimensions, so the gaskets need to be included. For oil pans either way will work. When in doubt, include the gasket and keep the coating very thin.

ALL the surfaces need to be clean, dry, free from any residue.