I had the same concerns as you when I first started making my own LBB capsules more than 10 years ago.
Here is what I did to make the mixing process easier.
Firstly, since the powders are almost all of slightly different color shades, I built up a batch by mixing part batches of 2 or 3 powders in a small clear glass bowl where you could see how well they were mixed by mixing until the color was even throughout the mixture. The ones of similar color were mixed in separate small batches with other colors until each of the small part batches were uniform in color and then bowls were combined and mixed further to ensure the total batch was again a uniform color. This satisfied me that the final all-inclusive batch was as uniform as I could possibly make it and was ready to put into capsules.
My first batch was using 50 grams as a part size and my mixing was with clear glass bowls and a regular small stainless steel wisk hand mixer. I now mix slightly larger batches with 4 ounces as a part size but still in clear glass bowls and with the same wisk.
I then transfer the completed batch into a large plastic bag. As I encapsulate by hand with a small 24 capsule filler, I just use as required from the large bag and make perhaps a months or so’s worth of capsules at a time.
Making the LBB at home allows enhancing the formula with Olive Leaf which MH has mentioned and I have been doing for several years. When encapsulating a batch I occasionally also add a drop or 2 of Oil of Oregano to each capsule for short term use.