Even a piece of plastic cut from a milk bottle. They can be mighty useful things for impromptu funnels from their handles, and containers for small things (read crap).

About your old Lead clamp if it isn't broken you can take the bolt out en saw the slit in the lead open with a hacksaw. then there will be enough space to tighten the bolt again. I did so a friends car last week, worked well.

I thought I measured 20" the other day. I stopped by AutoZone on the way home from work and the closest I cable I could find was 25" so I went with that one.

It fits much better than the other one. I wrapped some electrical tape over the bracket just for extra insurance.

Don't spoil the ship for a h'aporth of tar. Cover that whole end in tape, or cut a piece of insulating rubber/plastic and put over the base of the terminal.
Good clamp though.

The danger is in using a spanner to undo or tighten and shorting out - but you won't do that, because you always remove the Earth clamp (-ive) first - and replace it last, won't you!

I've got several sheets of GoreTex I use as gasket material that should make a good insulator. Only problem it's white. I'll look down in the maintenance shop at work and see if there is any black rubber material available.