I bought a couple of gennou heads from Tomohita Iida, and it's time to fit some handles to them. Having always bought my gennou with handles attached, I'm not sure how much of a taper the socket should have. Just a slight amount close to the rim, or a more pronounced taper towards the centre? The one, a copper head by Kondo, has nicely finished, parallel walls. The other, a funate by Susa, is a bit more crude, and actually slightly concave on one wall. How much do I need to file them to give them the right shape?