Filemaker doesn't provide a good scientific format for numbers. Has anyone come up with a way to convert a number to the exponential form with a specified number of significant digits and appropriate rounding? For example, 0.0003258788... would become 3.26E-4

I'd check sites such as the Brian Dunning site that are used to share custom functions to see if there's a CF for this. I'd expect that someone has already worked out the math needed to do what you want here.