Yes a ball head will give you the freedom to frame but it needs to be connected to a dove plate which then connects to the saddle of the mount. The L camera bracket suggested provides the dove plate and freedom in one axis to swivel the camera. The other axis can be set by rotating the declination axis, (or connect a ball head to the L bracket).
This is what I was thinking although this one is a bit pricey:
https://www.highpointscientific.com/...mount-vdup-bcm
Other types at
https://www.highpointscientific.com/...ll-head-mounts
If you already have the ball head then you just need the dove plate:
See
https://www.bintel.com.au/product/or...v=322b26af01d5
Either strainght dove plate+ ball head or L bracket as is or with ball head will work.