This is my GCI coaster that I have working on for the past week or so. I am using the simple auto-supports (yes, I know its lame) but I don't have the patience to do all custom supports. That being said, I am building the wide supports by hand. Some can be seen in the pictures below. Also some 3D's are done but some of the textures aren't exporting from Sketchup, is there a way to fix this? Here are some pictures.
If the no texture thing you're talking about is making the beams black ignore what I said below.
If the black I beams in your crossovers are indeed actual no limits supports, then I suggest you make them very dark grey instead of black (well everything very dark grey instead of black actually) because it makes the textures pop out more for some reason.