Does anyone know what these letters mean?
This answer is two months late; I hope you still need the information.
The position in your first image seems right. I still can't figure out what the first character is, but the second character is quite undoubtedly 妙 (Wiktionary) in a kind of seal script (篆书), though it looks a bit wonky.
Variation of character forms in seal scripts can be considerable, but I have an example for you - you can see it in the top right corner of this seal:

[&quot;妙吉羊菴&quot; by San'geng Xu (徐三庚)]
The left halves of them aren't exactly the same (one more stroke in the image you provide), but I'm inclined to think that's due to a misinterpretation of one long stroke as two separate strokes.