Question. I have a wheatstone, C/G concertina, bone buttons, seven fold. My left hand is not as strong or fast as the right hand. I have trouble balancing the two. I am wondering if pro players use that white powder to help fingers to stay on the buttons. I tried buffing buttons with light emery paper then stopped. Should I make the buttons concave.? On the topic of the folds, would I be better off with 6 folds. I am working on simple jigs and reels. On my own. Welcome any advise. Jan.