I am putting in a subpanel for my workshop. I need another 240v line, so I
am ripping out the two 120v lines and the 240v line I have already put in
and replacing them all with a subpanel. Wish I had done it right the first
time, but that boat has sailed.

I am running #6 copper. As I read it, it is good for 55a, and since there
is no 55a breaker, I can use a 60a. Is that correct?

On the other hand; the most I will ever ever use at one time is a bandsaw
and DC, which draw 27a together (which is why I need another 240v). I
happen to have a 30a breaker. Any reason not to just use that? It is over
the 80% rule, but I presume that applies to the wire rather than to the
breaker. If it trips, I can always replace it.

The #6 was only a few dollars more than the #8; so what the heck...