Get Tom's slide. Sha game changer. Seriously. Adam, get one from him. My Sha has never felt so alive!
@OP: Sha carbs are not tuned the same way other carbs that contain multiple jets for controlling different throttle positions and have needles with tapers. The only thing that controls everything is the slide. The issue with the low end is the lack of adequate fuel and air due to the majority of the vinturi being blocked by the slide. Tom's slide helps with this by having some boost windows in the wall of the slide. You can make your own with a very fine drill bit, or grab one from Tom. I also tried the 3d printed one, but it was not as easy to tune.
The benefit of this style of slide was that it allowed me to make sure I was jetted properly for the top end but did not bog out my low-end. It let me go up a couple jet sizes as well.
The other important thing on Sha tuning is their screen pack. It is important. But you can remove screens to find just the right mix of air. The only other filter that will work if you want to ditch the screen pack is a good foam filter. But too dense of foam and it will never get enough air. The mesh screen filters do not offer enough air restriction on their own so you still need to run the screen pack.
Lastly. Shas have an air leak at their clamp you must have an o-ring behind the shim that goes into your intake. The o-ring is the only way to stop that air leak.