Well done for getting how you want it. The best thing about the method we have used is that it is simple to put back to stock operation by simply removing the bridge and plugging the pedal switch back in.
Yes, the starter generator switches over to charge once the engine is started and the revs rise above a certain level.
On the carb, there is a screw that will hold the butterfly open at a preselected amount. Take a look at the attached image and you are looking for figure 6, item 3. Screwing it in will raise the idle and screwing out will lower it. You want to set it low enough that the cart will not try to drive off at idle but high enough to keep the idle nice and smooth. Basically, set it so that the clutch does not start to close until you push the gas pedal.
briggs.jpg
Just remember when making this adjustment, to have the gear selector in neutral to prevent the cart driving off if you raise the idle too much.