After having read discussions on the subject,. I've decided to do a test to see if grit has an actual benefit.
I divided a bin of EF's, not by actual count or eight but by approximate handfuls so there may be a slight variation but not much. I separated the worms from the castings then divided the castings and fresher bedding on top making each as equal as possible. They were put into the same size kitty litter buckets and allowed to acclimate for a few days.
While they were acclimating I made about 1/2 gallon of shredded newspaper and coffee grounds that I innoculated with some castings and allowed it to 'brew' for 4 days. This made a fairly wet pulp. For grit I used some of the clay I have in my soil here. It has a fairly small grit size.
Yesterday, I put a cup of the paper/coffee pulp with another cup of ucg's on top of the existing bedding in each bin. I then layered with a few inches of fresh dry shredded paper and cardboard and another layer of pulp and more fresh grounds. I did this 3 times then covered with more fresh bedding. The only difference was a liberal application of 1/2 cup of the clay grit in one of the bins.
I have no intention of disturbing either bin. I may need to add a little water if I do not see a little condensation in the bins. If I do, I'll pour in the same amount of water into each bin. My plan is to let the worms work undisturbed for at least two months without the addition of any food or bedding. I'll open the cover every few days to see if there are any noticeable changes in level.
I know there are a few variables I did not address but I think I started each bin as close to identical as I could.