I’ve found if you fill the bowl to the brim, as you suggest, you get nice round drops like you have pictured. If you want the “crowns” you see of milk drops, it’s best to have little or nothing in the dish (I use a plate). You want the drop to splash, so shallow is better for those shots.

I bounce my flash off a card or a coloured towel. It’s fun to put different colours in the background – patterned tea towels for instance – and you get interesting colours in the drops.