Master Cylinder Adapter

So i guess i would want to make sure that i made a bunch that would work and suit all needs of the buyers.I would hate to make them and not work for potential buyers.
I was thinking an overall length of 4.25" and width of 2.75" and a thickness of .375".
Would guys want a flat one or the fancy stepped looking one?
I would keep them bare 6061-T6 aluminum or possibly do some in Black Anodized if guys would want them.
I would also want to know the biggest center hole needed I thought 1-5/8 but (Lime Twist Dart )you mentioned 1-7/8. Would this bigger dia affect using a smaller?

Jason