Fortunately my custom caster has not had any problems so far and he gets checked regularly. I'm amazed that it is so, since he smokes constantly when working. Being from an area with LOTS of natural lead mines, I think lead gets a bad rap in a lot of cases.
Wouldn't just the wood density vary more than .010? You can keep the paint and sealer coat within .010? All the hardware used doesn't vary more than .010, when aggregated?
All my custom spin molded ned heads use a #2 Lil Nasty, anything bigger kills the action IMHO. I also have no head heavier than 3/32, above that I go to a shakey head.
I use a 5/0 and like the 1/16 ounce best, however I also use both traditional ball heads. The original ball heads have a different fall if rigged correctly, that works well for suspended fish.
Went fishless one night on Table Rock, fishing all the normal night time colors. Meanwhile my buddy on the back deck has a limit up to five pounds on Tomatoe Salt Craws. He only had six, finally he gave me one, second cast got my line broke.