I would not do this. Sorry to disagree but polishing it does not guarantee it will still be round when the guy is finished. As a matter of fact, I can almost guarantee it won’t be round. Several years ago, my machine shop sold out to a new guy and he had never run a crank grinder at this shop. He could do everything else very well. So I had to go elsewhere for one crank. That guy made so many mistakes on that crank he ruin it. Over polishing was one of them. It was .0005 out of round plus it had a taper on the end of each journal. Terrible job, it was. I caught it with plastiguage. I hardly ever use it. I found different brands of snap gauges will measure differently. I use Starrets before I got my dial bore guage. The snap gauges measure slightly bigger than a dial bore guage IMO. Maybe .0002. But as said before, it’s mostly in how you mic or feel the mic. After saying that, I think you’ll be fine with that. Now you could do what I do. I have the cranked turned FIRST. Then if I need some more clearance, I size the rods to the correct clearance. This works best for my shop.