Someone on the forum suggested this product to me and I wrongly dismissed it at the time. My apologies. My previous bike a BMW R1200RT was fitted with cruise control and although I didn't use it an awful lot, I found it useful and relaxing at times. I would never pay too much for a CC system and for this reason, I dismissed the aftermarket options for an electronic system on the CT.
For those who don't know, the Kaoko system is a mechanical friction lock that fits in place of the throttle side bar end weight, and when operated, causes the throttle to stay at a set position. It's not cheap for what it is (about £100 on ebay), however, it's very well made, blends in well and almost looks original equipment.
There are many variations to fit various bikes and even variations within a specific model. The part for my 2018 CT Highlander DCT was HND310 and took around 15 minutes to fit.
In operation the unit works very well. Obviously in setting the throttle at a set point, variations in gradient do effect actual speed slightly. However, in the situations where I most use CC, on motorways and dual carriageways, this wasn't generally a problem. Also, because the throttle can still be twisted, you can adjust your speed for the conditions without releasing the system completely.
In conclusion, I think the product is well made, works well and makes a long ride on dual carriageways and motorways more bearable. The negative is the price, but it's considerably cheaper and easier to fit than an aftermarket cruise control system.