F350 where do I jack from? / would this plan work?

You better check what the ratings are about.
Usually 3 ton jack has purpose of lifting passenger cars, who whole are below 3t.
Years ago I had bus conversion who weight 16t.
Having 5t jack stand, I figured the stand should support rear corner. (they should have big safety factor afterall)
When I open the hydraulic jack valve to lower it, the 5t stand split with no visible resistance. Just like knife in soft butter.