Looks good to me - I like the fins, although the 90 degree trailing edge close to the base plate might make them vulnerable to chips on landing. At first I thought the root chord was a little narrow, but it's an optical thing - I see the height and root are the same. The speed / altitude seems credible, commensurate with what I've got out of a similar 4" on 38mm J motors. Just another small point - the fillets on the .ork file are currently listed as cardboard and 0 radius - I'm assuming you'll be using epoxy and giving them some radius (...?)