I'll give the battering ram some more attention later this week, and really try to feel what it wants to do with my rear arm. Likewise with taking my x-step more diagonal on the final steps.
Film this if you don't know that it's clicking. Different drills work for different people, but this one worked for me.
To me it felt like if I started parallel stance, the ram would arc behind me, so I'd just rock back and forth until at extension the end of it was swinging "straight". Ended up my back foot was way closed behind me. And naturally your rear arm will swing forward at the same pace as your front arm, since they are both attached to the same object.
But since we're right handed, and trying to equate this to a disc golf throw, the right arm is doing a lot of the pulling and the back arm is kind of along for the ride. Also for me having such a big object swinging constantly around me, it forced me to open up that pocket and have a lot of room.
Once you feel this, the diagonal angle should feel more natural since you can visualize how the ram releases "straight" in relation to your intended target even though you are set up offset. Then do that with a disc from standstill. Then you should just try to get to this same feeling from X-step and you'll naturally move right to left, hopefully without thinking too much about following an exact line.
The end goal to me is to do what feels natural because each good position leads to the next. So the throw should hopefully end up feeling simple, and when you look at it after you'll be in all of the talked about body positions.