@TheHuth I think no matter what you go for whether it is jacket or BP&W, you will probably need to try it out and work out exactly what works for you. With your particular circumstance, I would definitely suggest a physical trial of any gear to make sure that it will work (if possible in the water as well).
One thing I would note with a BP&W set up is that the waist band doesn't tend to be too tight as the crotch strap is the part that does a lot of the work to stop it moving.
As REVAN says, a rubber belt might be an option as it doesn't rely on "natural landmarks" such as hip bones to hold it in place. Another option might be a weight harness which will put the weight elsewhere as well.
You can also put a fair amount of weight on the BP harness or the backplate itself which will shift it off the weight belt. A number of manufacturers of BP&W setups have methods of attaching weight in addition to simply having pockets on the waist strap: DSS have plates that fit to the backplate, Halcyon have a weight to fit the single tank adaptor (STA).
One thing I would note with a BP&W set up is that the waist band doesn't tend to be too tight as the crotch strap is the part that does a lot of the work to stop it moving.
As REVAN says, a rubber belt might be an option as it doesn't rely on "natural landmarks" such as hip bones to hold it in place. Another option might be a weight harness which will put the weight elsewhere as well.
You can also put a fair amount of weight on the BP harness or the backplate itself which will shift it off the weight belt. A number of manufacturers of BP&W setups have methods of attaching weight in addition to simply having pockets on the waist strap: DSS have plates that fit to the backplate, Halcyon have a weight to fit the single tank adaptor (STA).