Thanks for your comments!
The work lasted several months, especially looking for ideas for the final design.
In Spain they say that Queen Isabella of the stamps does not look like the authentic one, that's why I started this work with the effigy of a coin that was much more similar.
There were different tests, black background, grid background, effigy looking to the right, etc.
And finish 18 "stamps" MNG an 3 used with different cancels:
Coin of Spain:
I will keep visiting the forum, kind regards!