Thank you for sharing Robert - I like the WWs and specifically Spain is of interest to me - along with others (Ha!). I also was impressed with offset (now I know what to call that) and for me the ease of watermark identification was exciting.
I dug into a few of my Reina Isabella IIs to try to check and categorize - here are a few (note - I recognize my Scott#s could be off - my first attempt). Now I am the one that needs to get a hobby - I am all over the WW place - but I love it. :)
Yes :) you beat me to the punch r. cebrian - Robert: check these images out. These stamps I show are actually Isabella II stamps from Cuba (Spanish West Indies) - you can see the watermarks really well.