/\ changing my story above. cannot use 1/2emt if you are looking for a LOT of support. turns out i put it all together with three crossbars (4ft each) in a 6 foot span and when i stand on it, it gives a little.

fixed by adding 3/16" channel 2"x1" welded underneath the crossbars. no bending!

 

Where did you find the gutter mounts?? Thanks Coach.