380mm
This is another personal issue. I have found the 380 is a good compromise.
The 360 Nardi in one car makes the steering feel very direct, but it looks a bit too small when compared to the rest of the 1960s interior.
I have 2 beautiful Nardis in other coupes, which are 400. They look very period and are even more beautiful than the thicker 360 Nardi, BUT they hit my thighs when I enter the car, and they entail a lot of movement when turning. Ideal for manual steering when the arms get to work and doing this further away from the centre of the steering column is easier. But vanity makes me keep them, esp as one car is Siena with biscuit interior.
My `69 2800 CS has (or had) a 420 leather BWM wheel, again with PS, where a smaller wheel would be fine, but back then, wheels were larger (the Jaguar XKs of the 50s were 450 mm or 18")