In reality the size and content of the cheque is nearly irrelevant. In a previous life I used to generate cheques for dividend payments and apart from the MICR line at the bottom and the box holding the payment amount on the right hand side, basically everything else could be arbitrary.

I once even had to create cheques where the signature was literally a clip-art of the word “Signature” written in cursive. I had to confirm that was precisely what the client wanted three times over.