http://www.brailleauthority.org/sizespacingofbraille/sizespacingofbraille.pdf

Braille definitely has a set size. It’s the ideal size for reading with the fingers. Much bigger or smaller, and it becomes harder to read.

Generally, braille is set to a standard size. But there is a thing as Jumbo Braille, but it is a little harder to come by. The dots and cells are bigger for those with less feeling in their fingers. But normally braille is a standard set size. The PDF previously linked to gives great info.