Originally Posted by jsloan

Your chances are near zero either way. If UA doesn’t sell every seat — which, based on their inventory numbers at the moment, they think they can do — you’re going to find that many (most?) of the 1Ks on that flight will have listed for an upgrade with PlusPoints, which would put them ahead of you even if you use miles. Not because they used PlusPoints, mind you — PlusPoints and miles are treated as equivalent instruments — but because a 1K on an instrument will be ahead of a Plat on an instrument.

If you do decide to try using the miles, you may want to call and ask that they apply them only to the overwater leg; the rule where you can get the domestic upgrade for free if the overwater leg doesn’t clear only applies to Polaris-marketed segments, which LAX-HNL and HNL-SFO are not. (It’s probably a moot point, as your chances as a Plat on a hub-to-hub route are probably even worse than your chances on the Hawaii route, but you never know when massive IRROPS could pop up).

Your best bet for getting the upgrade is to watch your reservation for an attractive cash upgrade offer.