I've never found standard pole pruners very useful. I realize you have to be very careful but if you can reach the branches with a ladder you can do much more accurate work with a fraction of the labor.

I would think with neglected trees your needs would require more sawing than lopping. For this purpose a pole saw with a good tri-cut Japanese blade is extremely helpful. Look to Silky or ARS and expect to pay. However, it is still physically much easier to do the work with ladders instead of poles. Much easier to do quality work, without ripping bark as well.

Treecaresupplies.com sells the Marvin "Bull" pruner head for $60, which is what some pros use for commercial work. Instead of buying a long wooden dowel made of oak to use for a handle, you may want to consider buying a 20 ft length of galvanized top rail used atop chain link fencing. Drilling a bolt hole through the pipe is easy enough. If the pipe diameter is slightly oversized, a hacksaw can be used to make a 4" long slit through the center of the pipe to slim it down to fit inside the pruner head socket. I made a 4 ft pipe extension to further my reach to 25 feet plus when pruning very shady garden areas with giant trees all around. It is a "lifetime" pruner, and the exercise is good for you.