What parts are nickel?

[aceonbass]

The 70's clover leaf style tuners were made by Kluson, and appear to have been nickel plated due to the fact they don't polish up like chrome. The main distinguishing factor between the aluminum tailpieces and zinc ones..was that thee aluminum ones were aluminum. The cutout in the middle tooth appears on V and C series basses as well.

[aceonbass]

Thicken that part up a bit on the new tailpiece by widening the mass of metal perpendicular to the strings and bringing the edge of it closer to the saddles and you'd probably have a lot greater resistance to bending.

I don't think adding material in that area would help at all. The sides is where RIC has been adding material, and I believe that, as well as thickening the dividers between the strings, will help the tailpiece resist bending. In essence, make the current casting look like the old one.