If the speed switch is bad then you wouldn't have all the speeds in forward or reverse.
The switch that handles reverse and forward changes the polarity on poles of the speed switch I would investigate more before buying anything
Phil a friendly reminder they don't like the ebay links, I slipped one past Spike a while back. I hope it wasn't the reason for his recent demotion from super moderator to site moderator.
You can mold jaws or a cradle from bondo that will align the bait for drilling. Mix some fibergalsss resin with the bondo to make it more fluid. I used something very close to what you have described to drill belly weight holes.
I think what Jamie is attempting to do, is use the beads as load bearing surface above and below the screw eye. In doing so limits the vertical movement of the screw eye. Should also center the hinge pin in the screw eye.
If you keep the weight as close to joints as possible the more action you will have. The farther from the joint the weight resides the more force is required to move it.
The old lacquers are nitro-cellulose and newer lacquers are acrylic. The nitro stuff is harder but more prone to crazing and cracking. The nitro is still used, but not to the degree it once was