I have used the hollow Jameson poles up to about 20', but they can be hard to control even at that length.
I prefer a quality blade, to cut faster, with a hook at the end to help keep it in the cut - hate having to restart at that elevation. Undercutting branches is a real challenge, and if your blade gets pinched 20 feet up in the air . . .
Did you look at renting a pole saw set if it is for limited use? Would you feel comfortable renting an aerial lift? I know that that is a different skill set, but I know of several 'handyman' types who have done this to trim trees. Some HD's even rent them starting at $200 - $300 for the day.
Philbert