Soft solder, hard solder, it's not going to matter in this instance. The rocker connection certainly is not going to get hot enough to effect either joint.
In both cases the only concern I would have is cracks in the joints from vibration. This would be hard to miss when wiping the oil up.
Thank you John for the heads up about having to drill the banjos. The joints looked like brazing, so I didn't want to just take a torch to it before I talked to you guys about it.
Lee