Some things I think I've learned:
The worst part is carrying the 8x3 dock sections out. They're heavy and nothing can be done about that. Maybe I can devise a way to roll them out, or a ramp to slide them in--like launching a boat from drydock. Mine is constructed with pressure treated 2x6 boards--probably the heaviest option of all.
There is a Youtube video that shows the post installation. Leaving all the hardware attached to the dock sections would make it much easier to drive in the posts than leaving the crosspiece clamps loose like I did. Even loose the clamps tended to grab the post as it was twisted in.
The video also shows a support post being used to hold up the free end of a dock section as the posts were being screwed in. That's a great idea and sure beats just holding it up. Gotta make one of these for next time!