I would also avoid getting another male at this point. Females take longer to get to size.
Of the choices you listed I would get another cinnamon. I like pewters, but I like the stage beyond that even more; sterlings, silver bullets and silver streaks.
A lesser or butter would be cool too and a mojave on that note.
I've been meaning to ask about the sterlings, Silver bullets and silver streaks for a while. How are they made, and what are the chances of producing them? I haven't found any information on google believe it or not