It's gonna depend on how you want the butter to feel. Try making a tiny batch, weigh the dry-flo in and see how you like the results. It's mostly personal preference.
If I understand the description of Dry-Flo, the company website indicates it will absorb body moisture and facial oil when used in body powders or makeup.
Even though you combine it with butters and oils (i.e., body butter), is there any potential for it to counteract the moisturizing effects and take out moisture from the skin?
I don't find it drying. The only reason I used it was when I made a shea butter whip for someone who didn't like the greasy feeling. I personally 'like' the greasy feel as long as it fades quickly.
I think that may be one of the best things about soapmaking, and B&B, too. Taking some random stuff, using a little creativity and turning out something so pretty, useful and soothing.
The happy people are those who are producing something; the bored people are those who are consuming much and producing nothing. - William Ralph Inge