Ford’s owner instruction manual says to up shift 1-2 at 5-8 mph, up shift 2-3 at 15-18 mph, no need to double clutch at these speeds! If you’re grinding the gears at this recommended speeds then you have other issues like to fast of an engine idle, engine not returning to idle, transmission has too lightweight oil. If you get it right you can slide the gears without using the clutch ( just ask a good semi truck driver ) on a good day I could do it but I don’t recommend it. As for down shifting double clutching is a must that I couldn’t get right.