Don't use the plastic bolts, and don't use any nuts. And most important -- don't over-torque the mounting bolts. Just hand tight and then a tad more -- no muscle required.
As for the plate, it's for adding both mass and/or height to the cartridge. Mass if you are using a tonearm with a highish effective mass, height if you have a fat tonearm tube (like an SME V) which can touch the outside edge of some warped records at certain settings.
There's a great cartridge/tonearm effective mass matching table at: www.cartridgedb.com
.
As for the plate, it's for adding both mass and/or height to the cartridge. Mass if you are using a tonearm with a highish effective mass, height if you have a fat tonearm tube (like an SME V) which can touch the outside edge of some warped records at certain settings.
There's a great cartridge/tonearm effective mass matching table at: www.cartridgedb.com
.