We've got a booking sheet, one IFR vectored approach per half hour slot with various blocked periods throughout the day depending on where our highest traffic loads are predicted to be.
Non based training schools can only book on the day but our local schools can book theday before as can exam flights. Local schools also get approaches if they go out on an IFR airways jolly then pitch up whenever they want.
Invariably it goes tits up on a regular basis.
Oh and we don't allow holding at the beacon...............well not very often anyhoo.