Modified the backpack to look more like the original figure. Used a center punch to mark exact center on the piece that holds the backpack. Then started out with a 1/16 drill bit and worked my way up... 1/16 3/32 1/8 9/64 5/32 11/64 3/16 - final drill bit size I feel that you should work your up using every drill bit size I used and not try to skip any sizes as not to ruin your figure. Remember to remove the wheel also and just drill very slowly and do not push. The drill bits will very easily cut this plastic. Center punched the spot I was going to drill and started with the 1/16 drill bit size. Final size cut Backpack attached with new peg hole it absolutely alters nothing in either transformation and can still be used in its original way.