IMO reserve the "stack of dimes" effect for TIG welding, not MIG. I also believe that if you are starting and stopping for more penetration, you should probably turn up the amperage a tick and weld at a constant pace. Why add another variable to the mix and make things more difficult?
The purpose of pushing the bead when using gas MIG welding is to allow the argon/co2 mix to clean the surfaces as you are welding. Same thing with TIG, always have the torch angled in the direction of the weld. Many times I go ahead and use the torch with a moderate amperage and no filler metal and let the argon clean the surfaces before actually making my pass (TIG).