Pat Barber writes:

I would do 10' with 2x6's as studs. The "extra" cost will not
even be noticed and that extra room in the wall can be super
insulated. Super strong and roomy. I have 12' ceiling and that
is excellent. I truly regret not using 2x6's when I had the
chance.

I'm already ahead of you on the 2x6 studs. Energy costs aren't going down
any time soon.

I am most likely going to go with 10' walls even though the expense is not
insignificant. 10% more interior/exterior sheathing, siding, and studs
are required which is at least $1000 additional. $1000 doesn't sound like
much, but my budget for this building is tight.

Brian Elfert