Why not cut the pocket deeper? With a 8x8 sill you would still have 2" below a 6" pocket. If I recall, Brungraber once said 2" under a pocket would work. Anyone else heard of this? What is the rule for pocket depth? 5/8 the depth of the sill is one choice so you could safely go to 5" deep pockets on 8x8's. How about 9" deep sills?

I see a ratio of 1:4, I also see a steep curve leading to the reduction. At least this is the case with my adze, I could not cut that curve with it. It would have to be extended for the adze to work properly. When ever I get the chance I put them in upside down and adze to the top of the sill then flip them over. In general I use the length of the adze head plus the width of the blade back from the end to gauge where to start hacking. This is adjusted to how deep I have to go.

I just noticed the "or more" note. Well, maybe it would be close, the curve. At one time I measured out the curve, silly me.