Castle nuts are a pain. I often joke with the 1st AC as I'm tightening one that "this is the hardest part of my job." A gentleman recently emailed me looking for info on castle nut wrenches. What are they? Where can I find one? etc. Castle nut wrenches are simply a wrench which uses leverage to loosen or tighten castle nuts (which are forever loosening up on their own when you don't want them to, and won't come loose when you need them to). The wrenches are a handle of about 8" with a castle nut sized ring on one end. The ring has holes around it's circumference which fit the "nubs" on the castle nut and allow you to easily tighten it. Chapman started sending them out with their dollies a couple of years ago. The catch- those wrenches don't fit all castle nuts and don't fit Fisher type castle nuts at all. I usually use the handle part as a lever to loosen the nuts and never even attempt to use the ring part. You can also use your dolly wrench, a crescent wrench, a lifting handle, or anything else that you can fit between two nubs to use as a lever. Although it is discouraged, we've all also given up and started using the lifting bar as a "pool cue" and striking the nubs in a fit of rage to loosen the nut. The guys who come out with the remote heads often have a really cool universal wrench that fits everything. Instead of a bunch of holes, it had a series of cutout "teeth" on the inner circumference of the ring that fits everything. They will often tell you where to get one if you ask. We had one tech acquire one for us that we use on our crane.
Long have I pondered on this fascinating subject and for me, the answer seems to be using the dolly wrench as a lever. I've done it so much that for me it is now just the quickest way to do it.