Marie...
First and foremost...your knees...technical diving...depending on interests...and required specialties...involves considerable ''task loading''...remembering also that physical limitations never improve or disappear as you age...they only intensify...
You may want to consider visiting a tech specialty shop in your area...and getting kitted up in the shop...and or the shop pool...to see what you can manage...''comfortably'' being paramount...
If doubles are out...you're looking at large singles...ranging from 100's to 133's...there's even a few 149's still around...over and above this...you're looking at slinging...stage/deco/bailout cylinders...these could be as small as 30's or 40's...
Having said that...your depth...bottom time...deco time is going to be dependent on the volume of gas you can comfortably manage...
Earning the skills and having the time and money...rebreathers are a lighter alternative...but you will still have to manage off-board gas volume as well...
Before you head off on an expensive adventure that for physical reasons may be unobtainable...source knowledgeable people...ask all the questions...try all the gear...sign up for try-dive sessions...including rebreather...find out what you can manage before you take any tech courses...
There are lots of fabulous wrecks in in the Great Lakes...located at the outer limits of ''recreational'' as well as off the coast of Morehead City and Beaufort North Carolina...absolutely nothing wrong with being an ''experienced...proficient...AOW diver''...
There's more wonderful AOW wreck sites than you'll ever see in a lifetime...
Proceed cautiously...and what ever you do...don't get talked into buying anything that you can't comfortably manage...
Peak performance Buoyancy is always a good start...as is navigation...
Stay Safe...
Warren
You’re a bit late to the party! . Read more of the thread. A lot has happened since Aug 2017 when I started it. Thanks for the comments.