As far as increasing the size of the hole, that's never worked out for me either. At least, not a smooth round hole in plastic. I think you're better off plugging the existing hole and drilling a new one with the right sized spade bit. But that's me.
Thanks for the suggestion Tom, I think I'll do just that. And you think a spade bit would work better than a stepper for plastic? I've never really drilled thru plastic before. I might take the lid to Home Depot and ask them the best way to do it. The only other way I can think of is maybe a hole punch, heat up the lid and hit it hard.
I'll let ya know how it works out.