Stephen Johnson wrote:
Does it allow you to move both hands independently, or are they gripping something together, and remain locked at the same distance from each other during the movement?
Another degree of freedom with dumbells is that you can control the angle of your fists around the vertical body planes (e.g. fists parallel to sagital/frontal plane). I can't do barbells pressese because of bad shoulder, but I can do light weight (2X10 Kg) dumbells with the right angle of my fists which was easy to find using pain as a guide. Rotating the fists thruout the press in some kind of Arnold press variation I can get to a course of zero pain altogether. I don't know what will happen when (hopefully) I will up the weight. In the meantime, that is almost the only exercise I can do for my shoulders, with the exception that I can also do Smith machine sitting press, maybe because there is some degree between the body and the arms as the chair is slightly inclined backwards to allow the weights to get under my chin. Dumbells upright row is another exception, but there are those who argue against that exercise.
Of course YMMV, but you may want to try any of the above.
Disclaimer: I am no expert, just a beginner, but I do have a lifetime experience with joints/tendons pains