A click or how much it click depends on the method used to jailhouse and how tightly the space is filled.
Orings leave no gap for the slider to move (depending on the rings), JSpacers leave little to no space, while my original wire method leaves a teeny gap which allows for a click, however, it is dampened and depends on how well you wrapped the wire and if you pre-squished it or not (the feel can be very inconsistent until they squish down).
Speed switches probably should not be jailhoused as they are already very close to actuation before you jailhouse which reduces travel by half. On a speed switch, the travel is already cut by 25-50% half so you run the likelihood of sitting on the bump/actuation point or even passed it depending on how the switch is designed and how thick your spacer is.
You don't want to sit too close to the actuation point, I found this out while testing copper and bronze switches, too little travel before actuation point along with a flat spring rate causes them to almost feel like a linear switch. You don't really sense the actuation point because almost as soon as your finger starts to press the switch it starts up the bump.
Think of a speed bump in your car, if you start with your front wheels against the bump, when you start moving your front wheels are already on the bump. It's not going to change directions or experience a change it's going to go up the bump, crest, and fall off the back side, you never feel the rise. This is actually how linears work, it's just a long ramp (like driving over a hill). On the other hand, your back tires are rolling along smooth then hit the bump and creates a change, which you feel.
Personally, I've found anything less than about 1.2mm travel is to little.
Yes, that is extremely precise, but it has to do with how the bump is shaped, remember, it's not a sharp cone or pyramid, it's a gently rounded over bump and the actuation point somewhere near, not at the very top. You have to account for ramp up and rounding over. Which on blues is just about 0.9-1mm wide.