The sole advantge of having *A Gold status in another carier, based on your profile, would be to get to RCC without paying any fee whenever flying UA domestic.
Varig allows you to accrue status based on your best 12 months in a row. Moreover if you accrue the 50K any month next year you'll have it till 31.March.2005.
Varig won't offer you any bonuses unless flying RG or RG subs.
Check Varig's website if you want to enroll.