I'm making a channel for the bunna o-ring and I'm trying to figure out how deep should the channel go. My estimate is 80% of the diameter of the o-ring, regardless of diameter size, but I'm not sure, can anyone help? Before I show numbers let me warn that this is for a giant block, 8x18" for a passive radiator and that the smallest width our CNC can make is .25". Here's a simple sketch of the channel and o-ring's cross section: