when all else fails use what the manufacturer used, thats why they pay their engineers to come up with this stuff. permatex no3 is good, but cant be used on sumps. first hand experience when one of my mates decide to do that on his 202 hq, good fun watching him clean up brand new oil from absolutley everywhere lol go with silicone stuff. but permatex ultra black didnt work for me. with the proper usage and directions there should be no need for it to block oil gallerys and passages, except where copious amounts are used, or the product hasnt fully cured before being used. resulting in it corroding away into the flowing oil.
but dont let us scare you mildman lol