I know who I am... But what's my name?!

So. Aside from physical dysphoria concerning my chest, I am very comfortable with myself and my identity. Sometimes I forget that quite a few people don't know I'm trans (genderqueer) and so I end up outing myself (is that possible?) to them. I've had a couple people ask me what I prefer to be called and I'm like ???????

Basically, I have some names that I really like and I can't decide on which one to be my first name. I will most likely end up legally changing my name in a couple years since I'm not too comfortable with the name my parents gave me at birth. Too feminine for my tastes and I prefer masculine names.

Do you know of any methods to find which name fits the best?

I am stuck juggling with Sigfreid, Sigmund, Ivan, and Dietrich.
If I were to be named Sigfreid or Sigmund I would most probably use the nickname Sigi (Siggy).

I am an indecisive person so this struggle does not surprise me in the least but it is no less frustrating.

Also, I have 6 siblings, all of whom have very English or Irish names. It's probably the only reason I haven't really chosen Sigfreid or Sigmund since they are so starkly different in style and sound.