Usually, to use iweights, you just insert "[iweight=v005/1000000]" into the estimation command, before the comma (options come after the comma).

Omitting the other adjustments in the svyset command, for clusters and stratification, will affect the standard errors and confidence intervals, not the estimates. I believe that xtset and svyset are not compatible in the current version (14) of Stata. I'm not 100% sure about this--I hope other users can contribute their experience.