I think you have good ideas here.
If an expansion is kept for longer I'm sure it will produce faster gains. For example,My penis elongation wrap, are taking advantage of this. I believe this is the reason I have not needed erected stretches to this point, to cement my length gains progressively.
My penis is kept semi-erected back and forth the entire day, if I do Kegels I will get an expansion against the wrap, and I believe this is beneficial for cementing gains. Sometimes I get fluid retention, but that's not often.
I believe this wrap I'm using can be used instead of a cock ring, and can be wear for a long time. You have the ability to adjust the restriction. I believe you can wear it really tight after a session for like 45 minutes, get back blood flow, and then put it on again.
Will your penis be fully erected with a cock ring?
I don't really know, because I have never used one. I did not know anything about a cock ring and keeping the expansion going, when I was doing girthwork with Bathmate pumps.
Please post a picure of your duro ring, that would have been interesting to see.
I will post s picture of it as recommended.