Crow belts for RV-8
I just replaced the Hooker Harnesses on my RV-8 with the Crow 5-point system, front and back. I bought the system with the shoulder pads and I do recommend them as they seem to spread the pressure over a larger area during turbulence.
Regarding the 1/4 inch hole. That's what works for the -8 both front and back. I'm not sure why others need a 5/16" hole but perhaps the plans have changed over the years. My plans are 1999 vintage and call for Castle nuts and cotter pins to allow for movement at the attach points. Since you referenced torque, Im assuming you are not using Castle nuts. Perhaps that's a change.
The only installation adjustment I had to make was to add washers on either side of the mounting holes for the two seat straps for the front seat due to the gap in the belt anchors (the ones that attach to the floor per Vans plan). The Hookers had spacer inserts to compensate for this. For the Crows, I simply used some superglue to hold a standard AN washer on each side of the belt's attach hole to keep them from slipping during the install. They fit and work great.
I like the Crow system due to its simple release mechanism. My wife has a hard time pulling open the Hooker style latch and during an emergency this could be an issue.
While I am new to the Crow system, so far at least, they seem to hold snugger than the Hookers. In my experience (11 years with the Hookers), all their straps tend to loosen up during flight. That's why I replaced them -- I got tired of continually pulling the lap and shoulder straps down tight in turbulent air. We'll see if the Crows work better.
During installation, you may find there is a lot of "extra" belt for some of the Crow straps. In my case it is the crotch straps and the front seat shoulder straps. Once you get them set up the way you want, you can trim or hide the extra length.
I also noticed that the crotch strap on the Crow belts is basically not adjustable in flight. So you'll need to experiment to find the right length for your body size. By contrast the Hookers did have an adjustable crotch strap that you could tighten once settled into your seat.
Chris