Converting a standard putter to Armlock

[the great spinks]

Hello friends,

In December I found a Bettinardi Studio Stock Armlock putter in the used section at a PGA superstore at a crazy deal.  I was impressively horrendous with the flatstick and bought it on a whim.  I've shaved enough shots off my putting that now I'm a somewhat solid putter.  
I have a 2015 34" Queen Bee face balanced putter that I want to convert to an armlock.  I know that I'll need to find someone that knows what they're doing to do the work, because I'm not that guy.  Beyond loft and lie and shaft length, do I need to be aware of anything else?  I'm looking for you guys to give me any watchouts that I may be missing.  

Is their any reason why a heavy, face balanced head would be an issue in an armlock?  

I know that I'm leaning to the stability shaft.