LOL, I knew it wouldn't take long for someone to be triggered.
If the OP has issue with their size of trying to figure out what size to buy, and that it could be the wrong size with a change in wetsuit thickness (or no wetsuit, or going up to a dry suit), maybe it isn't the right thing for them? While the harness of a BP/W is easily adjustable, maybe another product may be in order? It doesn't look like this is the right product for the OP. Yes, I get there are die hard SP Hydro users in this thread. Doesn't change the fact that this may not be the right product for the OP.
All good points, and this is exactly what I'm trying to work through here. I did try the small on with my 3mm (ok, it's probably closer to a 2mm at this point...), and honestly I didn't notice a major difference from the 7mm, which was unexpected.
A few points:
-moving the chest strap up and down didn't really seem to do much in terms of the fit or comfort (see pics);
-the torso length *seems* a bit short, but not sure how much that actually plays out in the water;
-otherwise the design seems interesting enough that I'm curious to try it in the water and see how it feels. Unfortunately there aren't any dealers in the area that have demo BCs to try. :/
I've never owned a piece of SP gear before this, but I took the recent loss of most of my gear as an opportunity (ok, excuse) to try out some new stuff that seemed interesting and different than what I've been using until now. That said, I'm not wed to the Hydros (the Cressi Scorpion and Lightwing also caught my eye), just heard good things and was able to get a decent deal on it with the exchange rate and VAT back, etc. from my LDS.
In the pic on the right, the chest strap is in the 2nd from top position...
..and here the chest strap is in the bottom-most position, and the tail seems about the same.