Just to address a couple of your suggestions, which are very good. The belts currently provided have pockets for the weights, so there's no issue with the weights sliding on the belt. It's the entire belt that slides around unless I pull it really really tight which then results in my feeling nauseated, so not a great solution. I will look forward to trying out the Mako belts that @MAKO Spearguns has so generously sent. That may be the solution that I need! I've also contacted our dive coordinator and will be making a donation so that she can purchase some other upgraded equipment. I know there have to be other divers that are having the same problems.
I do load the belt symmetrically. Most of them have 5 pockets, so I either load 2 5# weights on each end or put 5 4# weights in each pocket. If there are 4 of us diving at the same time, then it's a take what you can get situation, but I always balance the belt. If I end up going the route of the harness then I'll look for one with ditch-able weight pockets so that I have the option for using it for other diving if I want to.
We dive on hookah, so there's no tank to worry about.
Still, I appreciate your suggestions as I'm always interested in learning. I'm particularly interested in gear configurations as I'd like to improve my own. Plus, there are avenues of diving that I'm interested in pursuing that will require different configurations. Cave diving, for example, but I don't know if I can interest my husband/buddy in full cave. We love cavern diving, but he's a bit claustrophobic, so full cave may not be an option.
I think you will like the MAKO belt. The whole issue of a pocket belt sliding around your waist will be eliminated. However, 20 lbs of lead on a belt is beginning to approach the limits of "comfort" (for ANY belt).
Since you are diving hooka and need a lot of lead, another option might be a freedivers weighted vest. Most often, a freediver will select this option when a lot of lead is required. Frequently a rubber belt AND a vest are used in conjunction to better distribute the ballast and to enhance comfort. It might be something to consider, however I am not any type of expert on hooka diving, so I'm not sure how you would secure the hose or handle rigging.
The MAKO weighted vest is very easily and quickly ditched when freediving.
Quick Release Weight Vest ("zero drag")