Trying to cash in some Plus Points for an upgrade to Polaris. Currently there are 9 open seats, and I show as #2 on the upgrade list (with plenty of people after me though). However, I can't check in to my flight because it's international and my destination requires a visa (at least, that's what I assume is going on--all I know is, whenever I fly to this particular country, which I do every month, I can't check in until I get to the airport). Will checking in only an hour or so before my flight hurt my upgrade chances, or does it make no difference?