1. I used small eggs and total weight not including shells was just over 200g (7oz).
If your eggs are very large, the total weigh could go close to 50% more than what I had. Then please adjust the other ingredients, accordingly.
Slight variations to the total weight of eggs should not require adjustment.
2. Please refer to my post, Home Style Japanese Dashi Stock.
3. Move chopsticks or a fork sideways in the egg to beat the egg instead of using a whipping action. Ensure that egg whites are broken down into smaller bits.
4. I used 23cm (9") frypan which has the bottom size of 19cm (7½") in diameter. Any larger than this will make a flatter dashimaki tamago as the egg will spread wide and thin.
If the frypan is smaller you will need to add smaller quantity of egg at a time so that each layer of egg is not too thick. Small pan will make a thicker dashimaki tamago.
5. Drop a tiny amount of the egg in and if the egg cooks gently, making a sizzling noise, the frypan is ready (about 180C/356F). If the egg cooks instantaneously, the temperature of the frypan is too high.
6. It is important to shape the first roll with even width otherwise you will end up with deformed rectangular dashimaki tamago. You could also gently press down the egg roll using the spatula if the surface is uneven.
7. Until you are used to making dashimaki tamago, I would recommend using a measuring cup for the egg mixture so that you can cook the same amount of egg mixture each time. It is important to cover the entire frypan with the egg when poured.
8. If the shape of the dashimaki tamago is uneven, you could correct the shape while it is still hot. Place a baking paper over the egg and use both hands to hold and press to shape it (see the step-by-step photo below).
If you have a bamboo mat which is used to make sushi rolls, then you could place the dashimaki tamago on it and warp it to shape. This will make a dashimaki tamago with round corners.