In reply to Kemics:
Hi Kemics.
Sorry mate, I don't know what's wrong with my brain at the moment, but for some reason I said 3/4" ply when I meant 4x2 timbers! Basically I'm an idiot
Anyway yes, with the 4x2s, I still get a bit of flex.
It may be worth putting a few different cracks side by side and joining the whole lot together with carriage bolts. That's what I've done anyway. I've got a ring locks crack, a tight hands/wide fingers and a perfect hand crack - so three side by side. The whole thing is pretty wide, but definitely worth it.
The advantage of having the perfect hands (could replace with perfect fists) is that whilst relatively easy, you can train with one hand in the hand crack say while you have the other hand struggling with the ring locks, or hands in ring locks, whilst feet are in the hand crack etc.
Mixes it up a bit and makes it more usable whilst getting used to the more awkward widths.
HTH,
Tom