Here is a video of RYA Coach Assessor Elsa Chance tacking her Oppie from one beam reach to another in one of the Helford River Children's Sailing Trust's videos. The sequence for the helm sailing a Mirror with centre mainsheet is identical.
Points to note which are not mentioned on the commentry are
- Correct "dagger" grip on mainsheet and tiller extension
- Plenty of speed coming into the tack
- Having pushed the tiller across, and then rotated the tiller extension forwards, the tiller hand goes past the gunwale and over the water so you can "wave at the fishes"
- Weight moves across the boat after the sail has changed sides
- When swapping hands, mainsheet hand has fingers down as it grips the tiller extension.