So my girlfriend just picked up a harbor egg. 7’10 2 3/4 thick, 21.5 in wide and the tail is square about 15 (I am guessing on that.) It has some channels in the middle, single fin box set up. I was wondering what fin you might recommend? She is beginner to intermediate surfer. Transitioning from a very wide and stable 3 fin set up 9’0. usually surfs beach breaks 1-4ft. Hope that was enough information. Thanks in advance.