SWIM started just started his first extraction and was following Noman's Tek. He put his MHRB in about 3 hours ago and noticed there are still chunks. It was mostly powder but there were "clumps" of fibers. He said he shredded it in a coffee grinder. Should he wait until all the bark is entirely gone so there isn't any solid material in the jar before attempting his first pull?

The finer the material is ground up, the more efficient the wanted substances will be dissolved in the solution., but a few "clumps" of fibers in an otherwise well mixed or agitated solid extraction will likely only provide a negligable loss. I would't be concerned about absolute consistentcy or perfection. Move on to the next step. I do use a blender, however.

Yeah this isn't all of SWIM's MHRB so next time he will use a blender and get it ground better. But its a learning experience so he doesn't mine a little bit of a loss. He is about to add the naphtha for his first pull.

That's cool. You're not trying to dissolve the hard matter, you're just trying to get the alkloids into the basic solution. I actually prefer a coarse grind because it stops loose bark particles getting all about the place.

After you've done 2 or 3 pulls, leave the stuff soaking for maybe up to another week and then pull again.

The only thing you have to watch out for are dry clumps. As long as it's all mixed nicely and thoroughly wet, you can't go wrong.