Hello
I'm new to bath bombs, and the board as well.
It sounds to me like maybe you're using too much liquid? 3 and 4 tbsp of liquid seems like a bit much to me? Between the fragrance oil, and the coloring (assuming it's liquid) it should be moist enough that you shouldn't need to use witchhazel.
I use baking soda, citric acid, sweet almond oil, fragrance and liquid coloring, and I don't need witchhazel because they're already moist enough. If you add too much liquid (any or all of the above) the fizzing action will begin mine turn into a large blob lol.
When you are making your bombs, I find it easiest to push and twist a little as you're pushing the 2 halves together. It also helps to pinch the mold a little when releasing. This makes it fall out, for me anyway. They're tricky little buggers, and nothing but trial and error will perfect your recipe (I probably went through 6lbs of citric acid before getting anywhere) Hope I helped