tinkering with the idea of sidemount for rec diving (cold and warm water)

[Schwob]

@Schwob easier to get on and off the boat for most people, especially if the boat has narrow gates, etc. Less gear movement as well if you breathe the "stage" during the dive and leave the backmount bottle as your bailout.

going thru ship passages is typically a lot easier in doubles as well. The bulkheads are often not wide enough to get thru without rolling when you're in sidemount. In doubles you are no wider than a normal person would be so passages are much easier to navigate.

I don't think the redundancy in OW is really worth the hassle so I only dive a single tank. If the dive warrants true redundancy due to penetration, exposure, or environment, then it's a different discussion and will come back to what makes the most logistical sense based on the area that I'm diving

..
I now understand your point of view and I see the narrow ladder gate area on the boat as a potential bottleneck (pun intended) too. Don‘t mind rolling to fit sideways while UW and don‘t mind the redundancy, especially solo. And as I still use way too much air, I sure can use the volume. Next opportunity I will however play with a BM single and a SM single, just to see and „feel it out“. Maybe I like it better than BM & slung.