The payouts generally come around 24 hours after the last person registers. Sometimes it's quicker, sometimes a bit longer.
You cannot compete in the same type of RG tournament until any that you competed in previously has payed out. So, for example, if you sign up and play a RG Kiawah Front 9, you will not be able to sign up for another RG Kiawah Front 9 until the one you played in pays out. But you will be able to sign up the RG Kiawah Back 9, 18, etc (unless you had already played in one of those already and it hasn't payed out yet).