AGK said...
Hey mate, you 100% need a seat harness. God knows how you have lasted without one. The seat harness will do exactly what you think and lower your Centre of gravity and force to your hips and that will help you alot. It will also help as you lean in that it doesn't unbalance the kite anywhere near as much. You'll never go back once you get one.
Dont think i would agree with that^^^^^ 100%
Adam Koch seems to go OK in his waist harness

I think getting/giving advice on what harness someone should use is like getting/giving advice on what shoes are going to feel most comfortable on your feet.
So the only way to tell is get out there and try them. If you can find someone that is already using one at the beach then hit them up for a go or go and see you local retailer and hit them up to let you demo one.