A:
Instead of extra-full or super-full, I like to look at the points of constriction.
A regular Remington 12 gauge barrel is .730". So a .665 choke is going to give 65 one thousandths of an inch of constriction, which is pretty tight.
Different guns are different starting diameter, so you have to figure it on a barrel by barrel and choke-to-choke basis for comparison.