I would bid Iah 320 fo for first year. Don’t commute on probation if you don’t have too. Then at the 10 month point on property decide if you want to go to the 756 IAH (assuming it’s available) or 777 in SFO. You also get a chance to see if wait time for 777 or 787 in IAH comes down or not.

the long haul flying isn’t going anywhere at United. Go NB in base first year if possible. You won’t be flying that much anyway first year on the WB but you will be sitting around in a Crashpad boarded a lot your first year.

one last point point in case you are not familiar with UAL you can bid up in pay bands at any time but you cannot bid down. So you could go 320/737 IAH then put in a bid for IAH 777, 787, and 756 FO and if you hold any of those during your first year you move up to the next bid group while and at any time you feel frustrated with NB flying just bid up and out to where you want to be.

good luck