There are definitely set time dining options @superduper123, where you can have the same staff each night. For this ship it's 5:30 or 8:00pm, I'm in the 8pm sitting. All options should still be available, I just tried to make a "mock booking" on the RC site and both times and My Time showed available to choose. You should be able to choose a sitting by contacting your TA or Royal as discussed above.