OK, I have read that the weights of the Mexican Peso are quite consistent up until the early 1900's with exactly 24.4g of silver in them at 90% purity...which makes calculating the weight fairly easy.
However, I have not found the same information for the Mexican Real of the 1800/1700 period.
Is the 8 real = to a 1 peso?
Is the silver content and weight of a Real broken down consistently like it is for the peso? (aka, a 20 centavo piece has 20% of the weight of a 1 peso pieces)