I've never felt that I was putting down to much rinse. Before this I was running
Prochem All Fiber Rinse. It calls for 3-8 gph but it can also be used as a post treatment product.
I don't think I could get mine dialed down to 2 gph because my adjustment is so touchy. So I would probably have to adjust my dilution like you mentioned if I wanted to decrease the amount of rinse I'm applying.
I'm due for a bucket test on my inline sprayer because I feel it's putting down to much product, but I almost always mix my prespray to the directions of the manufacturer. When I get my water softner I may adjust it accordingly then.
@Dolly Llama check it out paragraphs.