I have no experience with any of the rear sights but have you looked at the string splitter?
This might give you another option.[;)]
I personally like G5's meta peep for a peep sight and believe I shoot alot better with a peep than without.
I believe truglow makes a peep sight with some fiber optic in it to help gather light. My dad uses that one and says it helps. I don't know for sure if it does or not.
Have you looked at peep sights with bigger holes like 1/4 inch and up?
Dont know if this helps but good luck!