Well i can speak from experience. Ive got a nasty sidearm drive. Im trying to get away from it and work on my backhand. I was sort of on the same path as you. I was sidearming beasts a lot, and loved em. They had the perfect amount of overstableness to get some nice distance out of em.
But as my sidearm progressed, and I was able to gain more and more distance and power into the throw, Beasts started to turn understable on me. At this point I started flinging my Starfire around. I now carry a 175 Starfire, a 168, and a 171 StarSL.
THey are really great for accurate sidearm drives... (For me at least)
Now when I wanted more distance, I started to try to convert over to my orcs for some nasty D. And I learned to control the HELL out of em. I found out that the more power I put into it, the more I was able to turn em over. But I found the middle-ground between understable-stableness to get max D in a straight line.
I also found that the lighter weight i went, the more I was turning them over. My 2 main drivers are a 173 Champ Orc, and 168 Champ Orc.
Heres a vid i made the other day
The first few drives I was just throwin, The last half I was pretty much aiming straight ahead.
The normal backhand drives are around 320-330 feet, But my final 2 throws are a 175 Champ Starfire, Which just goes straight and dives right..
The last throw, Is one of my max D drivers. My 168 Champion Orc.
Just look at how long it holds the line.....
In a nutshell, I use Champion Orcs for most of my max D Sidearm drives, and Starfires for more accurate but shorter drives.