[cad321]

In terms of the placement of the gears/bearing holes, if you decide to go with the stock ratio or any other one supported by the shifter, you can just take the layout from the CAD model provided by the manufacturer. This way you know that everything is layed out correctly. The ball shifters work great however if you make a custom enclosure (we are doing this and did it last year as well), make sure you have all of the proper dimensions. Last year we didn't have one dimension (distance from the pancake cylinder to the 44 tooth gear) and it screwed up the entire shifter. Finally for the machining aspect, we CNC'd the plates last year in our shop and they turned out fantastic! I wouldn't even want to imagine having to do it on a manual mill though. I would definitely suggest having access to a CNC, water jet or laser cutter for this.