Any potential problems with re-numbering electrical panel?
The accepted practice in most of the USA is to number the breaker slots. We number them odd on the left and even on the right from top to bottom. A two-pole breaker takes up two slots and therefore two numbers.

Some newer panel numbers are imprinted in the metal with this numbering scheme. Most construction blueprints also use this numbering scheme.

You can use whatever scheme you want this is just the common practice. The National Electrical Code requires that you complete a panel registry with descriptions of the circuits. As long as it is legible and logical, any subsequent homeowner or electrician should be able to follow it. 

Happy Day!