I would say that it is pretty important to have the frame on a pontoon properly adjusted on the tubes. However, from a rowing perspective, I've found that they are so easy to row that if you have it a little out of kilter you probably won't even notice the effect on rowing.

As Mojo says, balancing is best done once you and your gear are loaded in the boat. However, I don't know that it's necessary to have someone take a picture of you in it. If you aren't able to determine this visually, I suppose you could also always put a level on it.

Proper balance for the pontoon boat should be such that it floats evenly to slightly forward. Also, it's important to keep the weight evenly balanced from side to side.

John