I am not ignoring your questions about the possible upgrades, but to me I would think that with your disability something like 2 3x3 ebb and flow tables would be allot more less maitnence. You would only have 2 resses to worry about, or you could go with one huge res on both tables. You would only have to moniter 1 or two possible sourses of PH and PPM. With your system you will still have other things to consider if you change, for instance with any type of bubble system, temps are going to play a major role and that means the possibility of a water chiller which run half a grand at least, or the possibility of halling around 2 liter frozen water bottels a couple times a day. You would still have to moniter several buckets and all of the change outs would be a pain, I would think that you would want your grow to be as indipendent as possible, but I don't know your situation, but for my self I have a major disability like you and have to taylor my projects around that factor.
Adieu