Got it! Not 100% perfect, but we made it work well enough. Used the cert to buy our flights from YYC-HKG which came to C$1,250 in W. then paid 22,500 miles each for HKG-MAJ (via TKK and PNI), and finally 35,000 miles each for MAJ-YYC.
All in, quite a good result. I know we could have done it more efficiently in terms of miles, but we have quite limited time and not much flexibility. We got a $0 flight cost (after applying the certificate), New Year’s Eve in SFO, PZ9 on SFO-HKG, 2 full days in HKG and 3 full days in Majuro. Looking forward to it!