A few comments:

1) I would be cautious about raising the seat hight much. try smaller amounts, 4" or 6".  

2) My dad (at 75 with peripheral neuropathy and very weak legs used two walking sticks to get around.  He found he could still kayak by wadeing into about 12 to 14 " of water and then sliding a kayak between his legs and allowing himself to sort of fall back into the seat.  He would then use to hands to get each leg in.

To land he would pullup with a foot of space between him and the dock in about 24 " of water. He would lift both legs (one at a time) over the side of the kayak towards the dock. Then grab the dock or a rope loop and pull himself to standing.  The kayak would tip and partly fill with water but he would basically slide out of the tipping kayak onto his fee. Then walk, holding on to the dock until he was out of the water.  I have a few pictures of him with the most wonderfull grin on his face in the middle of lakes in Vermont.  

So my suggestion is experiment.  you do not have to follow the book on the proper way to get into and out. Whatever works for you is great.  

Ed  

   Raising the seat would make the WD12 very tippy. I found that using the paddle as an outrigger helps steady the boat when getting in or out at the shoreline. I have yet to try at a dock. I imagine it would break the internet if I posted that.