I thought this video did a good job of showing the changes I make to my throw when powering down for approach shots.
For this throw I needed a roughly 200' straight shot to the basket. I wanted to snap it pretty good and run the basket...with the hill behind the basket I wasn't worried about the come back.
What I like to do is generally reduce how much I rotate my body while keeping everything else the same. This is how I find accuracy for longer approach shots that are too short to throw with a run up.
Notice how little my shoulders and my hips turn, compared to my driving form. Also compare the overall depth of the reach back. How far I can reach back is severely limited in the approach form due to restricting my hips and shoulders.
I use the same grip for all backhand throws FWIW.