I figured you had been using my site since you had used the bit of tape to mark the tops and bottoms. I'm always cheered when people find my work useful.
Ah, the circled bit at the top in the 60s stamp pic. I'm decoding that as the s of Avedis in the Ottoman portion of the stamp. I'm actually going to replace that 60s stamp pic with a new photo where instead of a red circle I just put a red line one pixel above the top of the stamp all the way across. I realized that having the circle there keeps people from seeing some of the detail in that area, but a line just above wouldn't. The switch will be done so that the old image is still there (under the existing file name) so old links work. But if you got to the site and refresh you'll get the new version (one it is in place). Since I'm actively making updates it is worth refreshing your browser (usually ctrl-R) to get the latest version.
I haven't got a very good picture of a later 60s 1.5" tall stamp. I've got one on my 18" thin crash, but it is very poorly pressed in. This is the best photo I've been able to get:
[img]http://black.net.nz/cym2015/18-1275g-late-60s.jpg[/img]
although this was before I was putting tape on for very faint or incomplete ones. This stamp is reputed to be the same as the early 60s 1 3/8" but taller. But I haven't got lots of good samples because it's hard to trust lots of eBay sellers to even know that they need to measure accurately. For most it's just "3 does = 60s" and that's all they know...even though that has been known to be incorrect for many years now. But there wasn't a good online reference for them to know any better. *sigh*
I've got a few other 1.5" 60s stamp pictures, but not nearly as many as I'd like to get a good sampling of them to see how much variation there is in how they are pressed in. For instance, your lower case i in AVEDiS is most likely an incomplete pressing and the die has a slight low spot part way up the I. I've noticed a couple of broken lines in other stamps which seem to occur in the same place in the stamp, and that's why I started thinking like that. At first I thought I might have picked up a way to tell two different stamp eras apart, but no, just natural variation.
Anyway, the stamp pics on my site which are from my own collection (many but not all) are taken with an inexpensive Canon Powershot A580. That's now an obsolete model. The key thing is good optics and a macro setting, plus using a tripod. But that doesn't cost much.
And last, yes I don't see obvious visible hammering on the bottom of those which says "50s" to me. If you have whole cymbal pictures of the top side that would help as well.
Hope this helps. You have helped me tidy up some thoughts.