I have to agree --- apart from anything else, 'base-52' doesn't make it clear that the encoding alphabet is, in fact, made up of letters. It'd be just as valid

I have to agree --- apart from anything else, 'base-52' doesn't make it clear that the encoding alphabet is, in fact, made up of letters. It'd be just as valid to use 0-9, A-Z and a-p. 'base-64' is at least a defined term with a defined alphabet.