Hmm, still not sure I really understand, maybe post an image? I do the little lip on just about all of my floaters and I can't say I've ever really had an issue with it. Even if the surface isn't 100% accurate it usually isn't noticeable(but I'm anal about lining that shit up), even still in actual use a very light seam…
If you've got a hard edge or a soft edge there, both methods rely on the low being "clean" to avoid skewing etc. Removing the little lip isn't going to make it bake any better if you're getting skewed errors with the top style. Unless I misunderstood your post or something. But yeah, I could write a few page on projection…
Both methods take longer, with no significant benefit. You simply need to make sure the outer edge of the the floater matches the shape of the object below it. This is usually pretty quick to do even by hand. Learning how to do little tricks like this will save a loooottttt of time.
Throw some sort of deformer on there to try and match the underlying curvature. You also don't need to worry about putting the screw into the actual position. As Ace alluded to these kinds of details are called floaters and when you set them not to cast shadows they look fine when baked down.