First reaction is #50, #51, & #52 are really appealing to me. The green in #49 works and I like the use of the chain to circle the letters - on the outside rather than inside. #48's lettermark is interesting, and I like the idea, but something's not quite working there. I'd like you to play around with that, but on the other hand I couldn't say anything would work - so it might be dead end. I think focusing on variations of #49, #50, #51, & #52 would be better. For #44, now that I see #49, I think the circles are better than the diamonds.