I think it depends on why you are doing the BSD. I have to limit my carbs to 20g a day because more than that will spike my blood sugars and I would have to go back to injecting insulin. So for me bulgar wheat is a no-no.
Many people, however, follow the recipes in the books and do very well on 50g carbs a day. It does depend whether you are doing the BSD to prevent ever getting diabetes, or are already pre-diabetic, or have recently been diagnosed with diabetes or have had diabetes for a long time. The longer you have had diabetes the more insulin resistant you are likely to be. Which means you will do better on lower carbs.
So – if you are ok with bulgar wheat I would be guided by the portion size in the recipe book.