Gauge size of knob and tube wire

Seems like every home that I ever looked at with K&T is an abortion with hacks, splices, etc.
Another thing I noticed is how damn small some of the actual wire is. Did they make more than one size of single strand? Last stuff I looked at was at or under 15 gauge comparibly.

Would a smaller size wire be able to take more amps than its modern day counterpart?

An open air conductor can pass more current than an uninsulated one of the same size.

BTW- K&T came in 12 and 14 AWG