I beg to differ regarding your statement on the similarities between the Russian and Bulgarian WW1 uniforms. It may not be significant, but there were some major differences, and I quote:
- Bulgarians, as a rule, wore a jacket and not a gymnastiorka (gymnastiorkas were only worn in the summer as fatigues only or mainly it seems)
- They also wore the German or Austrian helmet and obviously not the Adrian helmet
- Not all Bulgarian units wore boots, in fact most of them wore the traditional opancj shoes and puttees
- Most, if not all officers, wore jackets that followed the German or Austrian cut. i.e. the pockets with 3 pointy corners (the Russians only had 1)
- Finally Bulgarians wore a haversack, something the Russians didn't (they had a larger bag).
There were also many halfway regular troops in the Bulgarian army, similar to the Russian Opolchenie.
So, in short, while there were similarities, I do believe that there are enough differentiating details that make this a very worthwhile addition to your current range.