Graflex clamp question

Hi, TCSS. First post here. I'm planning my first build, and trying desperately to read and research. It's overwhelming, but I'll get it. This will be my first saber, and I'm trying to follow the KISS system, while maximizing my satisfaction with the results simultaneously.

My question: I'd like to use a Graflex clamp (including one switch) in my hilt, and I'd like an extension underneath that which won't extend beyond the length of the clamp itself (excepting male threading). Perhaps this concept isn't practical for a build. Does such an extension exist? I can't find the dimensions for the clamp anywhere (or my Google-Fu is weak).

Sorry if the answer is painfully simple to get, and thanks for the plethora of knowledge here!