I use a lubricated, straight tip "14 FR" (I think that's the diameter) catheter. And I believe it's 14 inches long. Preventing UTI's? I make sure that I wash my hands and penis before using. So far (knock on wood), no problems. And regarding the (for sure) embarrassing aspect, I think it was more on me to shed the secrecy. I found that my close friends are very understanding/empathetic which makes it easier to use the facilities when I'm out with them, or visiting their home.
From me, I'd like to know how you all know that you've basically been successful emptying your bladder. As I mentioned in a previous post, sometimes the flow simply stops abruptly (making me think that my bladder is not fully empty), and when SLOWLY removing it there is no more to come ou. Then other times the flow goes from strong, then mild, then when SLOWLY removing it smaller/weaker flow to dripping (which makes me think that for sure my bladder is empty). What are other experiences like?