Hats off to you! you seemed to have narrowed in on something that might work!!
After watching some Ryker videos, I see how much the profile differs (from a Spyder) for the fueltank. Makes sense now.
Sounds like having slightly more height —either by way of ? a higher mounted pedal maybe, or? Small Footstool next to the bike? might be of help. Just ideas.
The higher you are over the Ryker, the easier (hopefully) throwing your straightened rightleg over the Ryker’s rear “should” be, is my guess.
Please keep us posted! And good luck with the stretches!