Eric on "[Plugin: Easy FancyBox] FancyBox with Contact form7 width of box"

Solved it. For anyone trying to accomplish this with Gravity Forms, the following is what worked for me. Your mileage may vary.

First, it's a good idea to give your form a custom css class in the GF Form Settings "Advanced" tab. Then in your stylesheet:

.gform_wrapper { max-width: 100%; }
.gform_wrapper.yourcustomclass_wrapper {
	position: relative;
	margin:0;
	padding:0;
	width: 600px;
	max-width: 100%;
}