I'm all for fellow "fans" of the Imperial Family thinking of their favorite members by whichever name they chooes, but I prefer the names that they, themselves would have used.
I have to be honest: "Lex" is modern, Western European or American and sounds like the name of some boy who's face would be plastered all over teen magazines...not the name of a royal Russian Grand Duke and Tsarevich who live 100 years ago.
For me, I like to learn about my favotire historical figures by finding out as much as I can about who they were. Alexei Nikolaievich was many things, but "Lex" wasn't one of them.
I apologize if my honesty is off-putting, but I get the feeling I may be one of the older members on the board and so I'm at an age where I prefer to speak plainly. If that's too much to handle, let me know and I'll tone it down.