What do I need to know about shellac?

Repairing an old chair that has/had a shellac finish.

Normally, I can dip a rag in alcohol and reactivate the shellac finish and redistribute it.  But this one doesn't have enough left.  I need to add another layer but it's my first time mixing flake and applying the finish.  I also don't have much expierence with mixing solvents like alcohol.

1. Can I mix it in a metal container like used for turps?  I bought one of these stainless steel containers when I started oil painting but didn't end up needing solvents, so it's brand new and eager to be used.  But all the tutorials call for glass.

2.  What's a good ratio of flake to alcohol for a chair?  It's real, bug shellac.   I don't want it to be so thick that it would take forever to dry.  Some shellac I've seen can stay sticky for months afterwards.  My memory says it's not enough alcohol at time of application.   My memory also dredged up the usual ratio of shellac flakes to alcohol is 1:3 by weight for french polish on a guitar.   But I've seen ratios as week as 1:10 and as strong as 1:2.  What would be good for a chair?

3. Is it worth while applying a second coat?  Wouldn't that just reactivate the first?

4. Anything else I need to know?

I don't seem to have a skin or breathing sensitivity to old shellac, but I'll be working outside anyway.