The reason so many convention jackets and back inflates have such huge lift capacities is because the manufacturer has to plan for the worst case scenario with weighting. First, most of them are weight integrated so that could mean weighting for a 7mm wetsuit or worse yet a drysuit with maximum thickness undergarments, and an aluminum tank. There is also the possibility of the diver being slightly or grossly overweighted in this day and age. This could mean a huge amount of weight on the unit, and in order to guarantee a margin of safety and to float the rig they put a gargantuan air cell on them.
I don’t believe you could ever find a jacket with an 18 lb lift air cell. That’s a custom thing
Right... though there is (was??) the Aqualung Outlaw with the 12 # (I think?) wing option.
When you switched from the DSS 30 to the Hog, did you notice a big difference in your diving? or going from the Hog to the VDH 35?
No. None of them make a big difference. The biggest thing going from the DSS was that it was a horseshoe wing. Everything after that has been a donut. The horseshoe could be problematic if I needed to dump gas while in a head down orientation. Other than that, they’re all very small differences. I think just about anyone would be very hard pressed to really tell a difference unless they were literally diving them back to back, on the same day, in the same condition.