Bashed knuckles are most often a consequence of swinging your tools with what I call a "hammer swing" - straight into the ice, think of the fact that what you have in your hand is not a hammer, but a hook, so insted of whacking your wrist into the wall, the wrist actually only rotates and at the end pulls slightly down at the point of strike. Having "spikes", "fangs", or home made hooks for your pinky helps also, when you do mess up your swing... They would help on a straight shaft also, but to be stable on the ice they need some metal teeth on ice contact surface like the BD Fang. Grade 4 is rearly very featured (unles you look at Wicked Wanda and alike so straight shafts with some hooks will be just fine for that level, you will also be able to hang on your shaft better, hence you can release the leash a bit so you will get more circulation and be therefore warmer. with a good clip leash you can even shake out and combine the advantages of leashless climbing with the saftey of a leash.