For safety and comfort in serious acro, a second lap belt is important. Hooker also sells a ratcheting seat belt I've used in unlimited machines that increases your comfort significantly. The tighter you are in the seat, the more comfort in negative manuevers. Even in a dual belted open cockpit Pitts, I've felt like I was peering over the top wing in outside loops.
I do not like the Vans belts because they are so easy to get a 'false' lock. Pax think they are latched when they are not. They are also of minimal strength materials.
Consider also that in an accident,the belts and harnesses are what separate your bod from that panel. Yes,heavier belts and harnesses are not as comfy but if you crash-landed, you would be so grateful for them! Save money somewhere else!
On another note, my aviation hero was world acro champ Bevo Howard (google him). Bevo used to fly a Bucker Jungmeister that was brought to the USA in the 30's by a prince on the dirgible Hindenberg. Bevo's long term desire was to eventually donate his plane to the Smithsonian. However, in a freak accident which was probably survivable, Bevo was killed when his old original harnesses failed. He had been encouraged repeatedly to get better harnesses.
A former hangermate Frank Eldridge suffered an RV-6A accident here at Falcon Field (see my writeup and links in Forums-'RV Friends Who Have Passed On'). Frank was thrown into the baggage compartment. He became a great proponent of buying and installing the very best belts and harnesses you could afford.
Also consider the high density seat foam for safety as well as comfort.
The FAA Regional Flight surgeon once gave me some advice. He said the two top killers of GA pilots were head injuries from bashing foreheads on panels, and burst bladders and organs from crash impacts. He said if you would only pee before each flight that would help some. Been glad to comply ever since!
