I have a DR backplate w/ a 1 piece harness and an oxycheq mach v wing. have been using it without an STA for 4 months now and fine with it. A diver however suggested that i get a STA saying it holds the tank better thus more stable and comfortable. Is it really worth the extra cost?
I recently bought a DR plate and venture wing and find it fine when I strap the tank on myself but the dive boat personnel would just tighten the straps with the tank at any angle so I found I had to redo it each time.
I've just ordered a pair of mini STA brackets just to aid initial alignment to make it a touch easier for me and as guide for others. Will have to see how much they help.
Some use a single heavy full STA one to add weight to the backplate which may be another reason for using one.
Trantor