In my experience, sidearm can be executed equally well with both short and long jump cues.
The following is easy to demonstrate in person but hard to describe in writing: one principle that is often overlooked while jumping is that you want to be bent at the waist and align the center of the cue with the center of your body mass. I see a lot of people trying to stand far too upright while jumping, which means the center of the cue is lower (closer to the table). This forces you to hold the cue too far towards the butt end and puts your shoulder and elbow into a contorted position. As a result, they try to force the jump with muscle/power instead of pop the jump with a light stroke.
The corresponding principle is to hold the cue with a 90-degree bend at the elbow. With a short jump cue, for short over hand jumps, your body mass will be closer to the table (farther down the cue?). As a direct result, getting your elbow to a 90-degree angle will bring the grip closer to the joint. For longer/shallower jump cues, the center mass changes and hence grip will be farther towards the butt of the cue.
For over-hand jumps, especially short ones with short cues, this makes it far easier to get the cue ball into the air, but it's difficult to aim because your line of sight is angled more extremely towards the cue ball and not the object ball. For longer and shallower jumps, using a longer cue, you can be farther away from the table and will have better line of sight.
For the sidearm technique, you still want to align the center of the cue with the center of your body AND maintain a 90-degree elbow. The only difference is the 90-degree is now on the horizontal plane instead of the vertical plane. The stroke is basically the same as the overhand, but I personally find it much easier to execute AND much easier to see where I'm aiming.