by middle fin do you mean the only fin, or are there molded fins also. the way your board edges depends entirely on the shape of the board, with the right board you will be fine without fins, and eventually you will be able to ride no fins very similarly to the way you would with fins. what board do you have, that will help with the fin thing.
and i know it has been said before, but there has been a lot of wrong information about cutting to clear wake to wake heelside. you want to cut in with what is called a progressive edge, that means when you start cutting in you have little to no edge, and you progressively (thats why they named it that) cut harder until you are fully on your heels cutting in, knees bent in a kind of pooping on a toilet position.
once you get good at a progressive edge and you want to get more pop, you can learn to pre pop, which is when you sort of force your board downward as if you were going to ollie, right before you hit the lip of the wake.
a good way to learn this and improve your ollies is to cut out a bit on your easy ollie side (the side that you would be on after a heelside wake jump) and practice ollieing over and over again as fast as you can, so much so that you are basically touching down and you have already ollied again. keep doing this until you can consistently rapidly ollie as high as you would with a single popped ollie.
and for the guy above who was trying railies but hasnt landed any, make sure you DO NOT look down at the water at any time, if you keep your eyes on the tower it will make it easier to take it out and come back in, also if you let your body fully extend and then pull yourself back in it is easier because you arent trying to stop the upward momentum of your legs and board at the same time as bringing them back under you.
ill do my best to help with any other questions you have as well