I think you may have confused people with the term "gravity" - or perhaps you're asking far too many questions requiring first-hand experience - hence, no responses for two days.
None of the atomizers you list are fed by gravity, but rather through the action of "pressure differential" (see below). There are some attys that might be considered gravity or "top down" fed, but there is also a measure of capillary action involved in the transfer of juice from the Serawool filler to the wick... so you really can't say they are fed only by gravity. A few to mention would be the Vapourart GP Spheroid and Heron, as well as the Gus Aiolos.
As to what works... because there are the originals, and then the clones that - may or may not be 1:1 - direct comparison can be problematic.
To say "I like this, but I don't like that" would require one to have tried all the originals listed, plus many of the clones as well. I've done it to a greater degree than many... but I don't do reviews.
Phil and
Todd have probably done more
objective reviews than any other 20 reviewers on the planet... with the key word being "objective". (OK... Todd does get a little "giggly" with some things, but it's more endearing than annoying)
Assuming that "the black edition kfl+ clone" you've ordered is 1:1 and well made, then you - among the tens of thousands of other KF design users - should be quite happy. This is assuming you can build a quality coil and wick.
Here is a selection of
links to a variety of resources that will assist you in your goals. If you scroll down to the paragraph titled "How tank type atomizers work"... there is an article about how "pressure differential", not gravity, is the functional control for most atomizers.
