I would buy PP outright if the price is right, probably the same as $600 the co-pay would be and a guaranteed seats in PP with better UG chances to Polaris. Using miles from there to waitlist for Polaris is a good investment. We were in Japan for cherry blossom this year and I was able to get 3 award tickets - booked very early. I’d definitely buy it as soon as it opens if the price is right and there is plenty of historical fare data to use as a baseline