I ended up using a lot of that for filleting and bedding in the forward half. For the really large areas that were mostly horizontal, it was all wood, but in those that were coved, we mixed in a lot of West milled fiber as well. This mix with milled fiber in it seems to weep resin less while kicking. In the more horizontal applications, it mattered less.
The consistency was much finer than ordinary sawdust, but probably not quite flour. More like coarse cornmeal. Inexpensive, and a natural byproduct of cutting a lot of wood
The plain wood dust mix doesn't trowel quite as smooth as the West powdered fiber mix, but it seems nearly as solid when set. Hitting it with a die grinder for cleanup before laminating over it feels similar -- maybe just a tad less rigid, but not by much.
