Panning clamp or Leveling base?

[BorisL]

Hello,
I am currently planning to upgrade my tripod components to allow for better panoramas. I am trying to choose between two panning setups - one using a leveling base, and the other using a panning clamp. I plan to use them with a ballhead like RRS BH-40 which already has a panning base. Both setups have their pros and cons:
- Leveling base allows you to level the panning base of the ballhead and that's all you need, but it is bulky and heavy and costs a lot (RRS TA-U-LB costs $215 and weighs 335g). It is also not easy to put it on/off quickly to avoid extra weight when you don't need it and only use it when shooting panos.
- Panning clamp, if bought separately from the head, is also expensive and heavy (RRS PC-LR costs $255 and weighs 336g), but more flexible in use. Besides, you can buy it as part of the ballhead and then the extra cost is only $160 and extra weight is only 182g for RRS BH-40. However, to use panning on the clamp, you must have the camera mounted perfectly horizontal, otherwise rotating the clamp will have camera view draw an arc and this will be obviously a problem with framing and stitching.
I am intentionally not discussing parallax challenges here (planning to get a nodal slide as the simplest solution) and not getting into very complex and expensive panoramic setups with specialized panoramic heads like Nodal Ninja. I just want to make the right decision on the simple panning solution leveraging the standard ball head.
What would you advise?