The stepper motors self park when engine is turned off. I just disconnect them before starting the engine. It's a bit awkward to start as the engine wont run under 1500 rpm so you have to hold the throttle open and whack it shut just enough to not stall it.
I use a TwinMax electronic carb balancer. It does the job easily enough. It will also allow you to check the throttle balance on the road. Mine stayed out by the same amount all the way to motorways speeds.