On a recent job I found that the actual planting wasn't much different between 2 gallon and 10 gallon -- if I had the hole already there. All sizes ran about 6 per hour. Depending on the shape of the pot. (I never see #7's here, but I'm guessing 14" across and about the same high.) you would need a 20" auger, or a 16" auger, over dig the hole, then scalp the sod in to partially fill the hole, jumping up and down to pack it, until you get up to the right depth.
20" means at least a groundhog, but more likely a small skid steer, or a lot of hand labour. With the skidsteer, it's a a few minutes per hole, then hours cleaning up the damage. With a ground hog it's 10 minutes per hole, and a few minutes cleaning up the damage.
My normal bid for this sort of thing, is the price of the tree, per tree. So if the Cypress are $50 each, then $50/tree. I'll modify that if the soil is hard. I turned down one job because there was no access for machinery, and the land should have been a brick factory.