Bulgarian split squats

Hey Everyone,

I was wondering how much others tend to use Bulgarian split squats, and what kind of gains they have achieved by it.
I have a really bad dorsiflexion, and of course I want to improve it and I am working on it, but until then most squats variations are out, I am a tall guy and all similar movements demand good ankle mobility. Until then, I use Bulgarian split squats. How much strength and muscle mass can I expect to get by it?
Thanks!

Once in a while I use them. Not as much as when I started doing Sheiko programs. I tend to feel it helps improving squat technique and cannot measure it in how much gained muscle mass one can expect. I know it is not the answer you want but it is the answer I can give.