hragarkissian- You can surf with the stock setup just fine but the more weight the better.
ShawnB- I use RPM as well and with all the weight we have we are usually around 3300 and 11-11.5mph.
As of right now we have 450lbs in the back locker, 1800lbs along the port side under the seats plus stock. This is a video of my wife from a few days ago. She just surfed for the first time about a month ago. The video doesn't show the wave very well from the angle of the video but it's tall, long, and very clean all the way to the front of the boat. There's no roost or white water coming right off the boat into the port side. The wave in the middle and right off the boat didn't clean up like we have it now until we added another 800-900lbs on the port side. We rode behind an Enzo 230 last week and hated it. She gets pretty far back toward the end and I can get farther back than she gets and still ride. She also just gave birth three months ago so she's doing great
She's already doing some poses and this was with the wave flattened out a bit to make it less steep and easier for her to learn to move up and down the wave (center tab down most of the way). Pic isn't very good as it was taken on an iPad. We have been behind a few boats now and the wave behind the X25 is awesome.