I inherited my grandfather's GEM a while back, I also have around 5 DE's and I prefer the GEM over all of them.
I had a similar problem finding SE blade myself, however a member in the UK was kind enough to send me some GEM PTFE coated stainless blades . You can get them from overseas but they mainly sell in bulk like 100 blades at a time, which is a lot of blades if you dont even know if you like them or not.
You could PM some of the SOTD boys who use Gems and ask them for a link to a good supplier.
If it makes it easier on postage etc I would be happy to go halves in a box of 100 if you like.
Grant