I've just found the added tour date for Bangkok.
However, according to BEC (the organiser), the date is not 22 May anymore. The new date will be announced soon.
And Rajmangala Stadium's exact capacity is unknown, but it contains 65,000 seats (excluding the inner field area). It was rumoured that it once contained 100,000 people in a political activity.
So this is not a sell-out place, but it will be interesting to see how many she will sell.