I'm a RBK and I use the Rampro swim ankle -
Rampro - Swimankle - runs about $800 or so - can't remember off the top of my head. Mt prosthetist gave me a cheap SACH foot to use and so far this rig has held up for over 2 years. When I'm ready to enter the water, I loosen the front and outside top adjustment screws far enough to get my current foot module off (Otto Bock Harmony HD vacuum system), put the dive leg on, tighten down and I'm good to go.
I'm a big guy, so I don't walk with my rig - me and my normal rig with an HP120 ready for splashing in is about 340lbs which IMHO exceeds the limits this ankle can take, which means a slightly modified entry/exit. Shore diving, my buddy helps me get my gear to the water and floats it, or I use a cart to get it to/from the waters edge. On a dive boat, I sit on the swim platform and the DM sets my rig down behind me and I face roll in after donning the rig. If seas are calm, I just toss it overboard (don't forget some air in the BC!) and jump in after it and chicken wing in while descending. I also have a 10' paracord line with clips on each end - if seas are sporty, I'll attach one end to the tag line, one end to the BC and float it that way. Once in the water, flip the switch, and the foot goes to 70º plantar flexed. Reverse when you get back to the ladder.
Biggest issue for me is water getting in-between the sleeve/liner and skin, especially on the second/third dive. I use the Velcro knife straps, one on the bottom of the sleeve tightened down against the socket, and one at the top tightened down where the sleeve meets skin. So far this system is working great and have done up to 6 dives a day with no seepage of water loosening the vacuum.
I do practice and recommend swimming/diving without the leg on to be prepared. The dive leg pylon has a snorkel keeper on it, so if I do have to take the leg off at depth, I just clip it off so hands are free.
If you want more info, PM your number and I'll give you a shout.