I am taking a work trip to Tokyo in April and am *A Gold (via United Premier Exec status). My employer wants to book me in Premium Economy on NH and then I want to use UA miles to upgrade to C. How do *A upgrades get processed by NH? Is this a confirmed upgrade or the standby variety?

I could also have my employer book me on UA metal and then get a guaranteed upgrade based on my status but it seems to me that the UA C and UA econ plus seats are vastly inferior to NH product. Am I correct?

Thanks

Drew