Altho it may give you a convenient attachment point at a couple places, keep in mind that the rail serves a bigger purpose than just being an attachment point.
You would be amazed at how fast a 2 ton puddle can form on an
awning. Once too much is too much, the water tipping point could easily be on the trailer side and really ruin your day if sitting under it. Not to mention the cups probably would not provide enough beef to hold that much
weight.
I lower one leg of my awning to allow water to roll off in a storm, but it requires that all of one end stay up as a "top" point to roll from. With cups.. I think it may just pull down the center of the cloth and pool anyway.