How much dry calcium hypochlorite do I need to buy?
I was looking for the same answer.  I found two answers online.  1 tablespoon of calcium hypochlorite to 1 cup of hot water.  or a inch and a half of calcium hypochlorite on the bottom of a quart mason jar.

use glass jars.

I used about an inch and a quarter in the 1 quart mason jar cause I wanted to save some of the powder in case I needed another application.  That way I could get 2 applications from one bag. It dissolved nicely with just a little bit left on the bottom of the jar.

It was about 5 bucks for a bag.

apply to wood and let it dry overnight. rinse well with water. some say use white vinegar to neutralize it, some say use baking soda. you will need to sand it again after it drys again.

how much calcium hypochlorite do I need to bleach wood?