Wirelessly posted (BlackBerry8530/5.0.0.601 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/417)
A few thoughts:
How many miles does UA charge for California-Hawaii in First?
AAdvantage miles are also redeemable on AS and HA; Avios are also redeemable on AS.
AA does not offer any direct flights between the Bay Area and Hawaii. If you redeem Avios for travel on AA, you will pay extra for the connecting flights to/from LAX. Better to redeem Avios on an AS nonstop from one of the Bay Area airports to Hawaii.
Amex occasionally offers transfer bonuses when converting MR to Avios. Keep your eyes open.
Getting four F award seats on any single flight at the lower award levels may prove challenging. Avios can only be redeemed for the lowest-cost awards on AA and AS.