Update after a few dive :
I ended up buying a Tecline Donut 22 Special Edition, which has a volume of 22L (about 48 pounds of lift). After doing around 60 dives with it, I must say it’s a very solid all-arounder.
I’ve used it in a variety of configurations, including a 12L and 15L single steel tank, a 12L steel single with a 12L steel stage, and a 2x12L steel twinset, with or without a 12L steel stage, both within and outside of the "recreational range." Don’t ask me why I’m using a 12L steel stage, it was for a very specific job in a very remote environment.
Yes, it does taco a bit with a single tank, but that hasn’t been a real issue for me. It’s very manageable as long as you're aware of it, and I didn’t find that it trapped air in any way.
I would still agree that using a twinset wing for everything isn’t ideal. Someone in this thread said that using a twinset wing with a single tank is like cuting a 2x4 with a hammer: it works, but poorly. After trying it myself, I think that analogy is a bit too harsh. To me, it's more like using a sabre saw (a do-it-all wing) instead of a miter saw (purpose built wing). Sure, it’s not as precise, but it still gets the job done pretty well.
All things considered, if I had to do it all over again (choosing one wing to handle everything) I’d probably make the same choice again.
