Transom swim platform.......How wide?

[mauryc]

A transom mount swim platform will be one of my first DIY projects. They have them all over ebay. Question is what size do I need. I guess I can wait until I have the boat home and measure, but I thought I'd pose the question here.

Thanks,
Maury

[msbhammer]

I think mine is only mybe 18"x15" I think. I prefer wider and longer or go custom. ;)