Sold on 10ft. Thanks all for the great responses.

My new plan is to lay 2 courses of 8" concrete block and then use
standard 8ft studs and work with 8ft sections of wall so I can tilt
them up myself. I will use morter to lay the block, screen after first
course and then fill the second course with concrete (or morter?) with
j bolts. Do I need to fill each block on the second course? or just
the ones with the jbolts?