No, if it's sold out at one park, it'll be sold out for multi, as well. If you don't have G+ multi prior to it selling out, you're not going to get G+ in the sold out park that day.
No, if it's sold out at one park, it'll be sold out for multi, as well. If you don't have G+ multi prior to it selling out, you're not going to get into the sold out park that day.