How to prevent oil leaks?, Surely it must be possible! Options

[ThinAir]

I've always believed that it is POSSIBLE to build a Type IV that does not leak, with either synthetic or natural oils. The question I've had is "how?"

This gets to "where do Type IVs leak from"? Now there are obvious places like oil pressure senders that can be problems from time to time when something malfunctions, but that's not the issue. It's more an issue of the kind of oil "seep" that results in the bottom of the engine being moist with oil, but you can't tell where it's coming from. It makes me wonder what kind of sealant (if any) should be used in places like
Case halves
Push rod tubes
Cylinder-to-case
Cylinder-to-head
etc.

Since I'm in the middle of a rebuild, I'd really like to do this right. When I got my training on overhauling Type 1s the sealant of choice was "GaskaCinch", but it's not 1980 anymore and there have been lots of advancements. What is available now, and where should it be used, to achieve a Type IV that does not seep oil?