Thanks Buffalobob, I was hoping you would see this and weigh in. As the case often is, something that seems simple and common sense often is not quite so simple, or at least there are things you need to be aware of.
I think I am going to try this with some US 869. It seems the formula is "mix slowly and carefully not raising any dust"......but get an even mix.
Thanks to every one who responded. Anyone else out there, or if you think of something else keep bringing it on, more info is always better!!