Although I have used SprintLayout several times for DIY PCB's they are made in Toner method, so need only PDF file, no idea about Gerber files generation...
I don't make throttles, only rewire some old Suncom SFS, Tm TQS, WCS, CH PRO Throttles, this mechanics that you see in pictures across this topic is metal parts done with laser cut by GVL224 or Divk - see announces in Buy/Sell/Trade.
But friction in then is simple, example Divik mechanics: