supports

i know this is a dumb question but about how far away or how close do the supports need to be to make it realistic?

Are you saying from one another going down the track? Cause that can all depend on the type and style of track, the height and the forces experienced. Some rides with stronger forces may need then to be closer and thicker then tracks otherwise.

screenshots?

I'd say generally about the length of the train. (assuming it's an everage size and not ridiculously long) Though it does depend on what forces are occuring at that part of the ride. Obviously a 5G pullout is going to need larger/more supports than a Zero G airtime hill.