Question re: activating biochar

I am planning on activating biochar with worm castings for the first time with the intent of adding the char at a rate of 10% per soil volume.

If I add 1cf of castings to 1cf of biochar and let it sit for a month ~ the end result would be 2cf of finished mix.

When adding the now activated char to the soil mix, would I count 1 part compost and one part biochar into soil mix - adding the activated mix at 20% soil volume as the char is now "diluted" with the castings? Likewise, the castings added to the char should be subtracted from the total amount of compost I'm adding to the soil mix?

Last question, is 1 cup alfalfa meal the ideal addition for the activation process? I heard that flour could also work which I have a lot of on hand.

To activate my biochar I put the EWC (and other goodies) in a sock and tied it off. Then threw the sock, some molasses and the biochar in 5 gallons of water and bubbled for 1 week.

I really don't measure any more, but tend to go on the lighter side when amending.