On my SS/FG a .75 chain gauge now fits in, is it time to replace the chain? The 1.0 side of the gauge won't go in yet.

I'm assuming I've got a 1/8" chain, will the tool I use to break a 10 speed Shimano chain work on the 1/8" as well?

On my road bike, I use a KMC with their master link. Is it recommended to run a master link on a SS/FG as well?

Any recommendations on what brand chain to buy?

Thanks!