Tips on getting a big guy on a wakeboard

I will start by saying I am a pretty big guy, 300+lbs. I bought a Hyperlite Apex 147 board, which was the largest board I could find. I have been trying several times and we recently bought a new boat with a tower. The tower has helped my progress. I have managed to get up somewhat but as soon as I get up, I lose it. I have had some people say i am too far forward which in some cases is true. Other times it seems like the board is wanting to move around and trying to get it steady is too difficult. So, does anyone have any tips/tricks I should try? I tried a smaller board just to see if maybe a lighter and more manueverable board would help but that wasnt the case. The big board definately helps. We have pulled the rope in to as close as 50 ft but I dont really find the rope length to make much of a difference. Any help would be greatly appreciated. I think my biggest issue is that while I am letting the boat pull me up, I end up too far forward in the process. I guess I need to figure a way to stay leaned back but still let the boat pull me up.