over the years I bought a bunch of different styles and sizes and brands of gland wrenches. Probably a couple thousand dollars worth.
None of them worked as well as a $20 hammer and a pair of channel locks and maybe a pipe wrench. If it didn't come out with a pipe wrench (rusted), it was to be replaced, if you ever did get it out (and I got a few out), the nut and barrel threads were trashed, and the cyl had to be replaced anyway. Once, I had to pay a machine shop to repair the threads and make a new gland nut because the cylinder was NLA. That one cost the customer over a grand but there wasn't any other choice. All the hydraulic shops said they couldn't do it either. Machine shop was last resort but it worked.