Water starting is easy to learn on any board, size isn't that much of an issue except that being able to uphaul for backup is important. All you need is enough wind and some basic instruction. Wind is one thing, but sail size is the other. If you are using a small sail, 4-5 meters, you will need a lot more wind to water start compared to a 7 or 8 meter sail. So whatever board you pick, make sure you are comfortable uphauling it in slightly choppy water. Lake Norman is pretty big and you could drift a long way if the board is too small to uphaul in small/medium waves. Stay close to shore when you are learning.
I learned on a longboard via trial and error in the 80's. When ever I fell to windward and didn't sink the sail, I gave waterstarting a try and before long, it just happened.
Formula 160; iSonic 111; HiFly Move 105; Tiga 263; '85 Mistral Superlight.
Maui Sails TR 11.0; 9.2; 8.4; 7.6; 6.6; Maui Sails Switch 6.0; 5.2; Maui Sails Global 4.5; 4.0.