If the flavoring is new to me, I'll usually start at 5% unless I know it's a super concentrated flavoring and then it's 2%. I'll wait roughly a week before making any changes. I finally learned that too much flavor is as bad as too little...... when I started DIY I used to put in way too much flavoring and couldn't understand why my
juice tasted so lousy. Now I take the conservative route and start low and add if necessary. Sort of like cutting a board..... if you cut it too short you are in trouble. If it's a touch long, you can always shorten it. You can't take flavoring out but you can add more if needed is what I'm trying to say....lol.