I get just as much spitback from the Stumpy as the Derringer. Or the Dinghy or any other tiny atty I've used. I think it's just the nature of the design. As to the building options, I agree that you can fit much bigger builds in the Stumpy but I'm not sure how that would help with spitback. I don't use Claptons or anything like that but from what I've read they just lead to even more spitback.
I also used identical builds in both attys (same juice as well) and found no real discernible difference in flavor. Other than providing an easier platform to install big builds, I'm not sure what else the Stumpy offers that the Derringer doesn't.
Haven't tried the in between posts build, maybe I'll give it a go later tonight.
Not just big builds, but more types of builds because of more room and a lack of a center post. And that one thing opens the door to other things and, to me, that ends up being a big difference---of course, if I only ran the same build on both, it wouldn't be enough of a difference to write home about. I guess that is the crux of it though. If you want to build the Stumpy like you do the Derringer, there wouldn't be much point unless you were keen on a deeper well and an easier build, which, for just those two things, is enough of a reason for some.
As to why I get less spit-back for the Stumpy over the Derringer, I dunno. I do tend to think that dual-post deigns are more efficient for wicking since there is more of an unobstructed channel for liquid to flow (bro science here, not peer reviewed research. LOL). And I didn't say it was about bigger coils that helped in that arena, just that you have more room to tweak your builds and try various things because there is more room to play with. I do think though that if approaching one atty and another with the exact same build that you will likely get a similar vape experience, after all, builds are very much a part of the flavor experience.
For sure though, try that in-between posts build. Of course to much hype always ruins it though. LOL
p.s. I never had a larg
er problem with spitback and Claptons, just about the same as normal. It's other factors like resistance to power, coil placement, wicking, over-dripping and whatnot (AFAIC). I do hate spitback though!