Accurate and honest measurments. That's the key.
I don't need a manikin to make a kilt unless your very oddly shaped. One leg is significantly shorter than the other, or your spine has a pronounded curve. And in those cases A photo of your self will usually clear up any additional measurment I might need.
Accurate and honest please. If your "a man of substance" tell me and I'll cut as required. But don't,whatever you do, give me your jeans store waist measurment. Kilts are cut for comfort, not to some fashion desigers idea of the IDEAL man.
Your mannikin is however a great place to hang your kilt when not in use. Placed in the middle of the living room it beats a copy of Vouge sitting on the coffee table for a conversation starter.