Oh as for the lap times, yea you have a variety of options as to what you can view on the screen while active. You can see the obvious like rolling lap, last lap and best lap. But you can also have the option of "difference from best" and stuff. I haven't messed with that too much yet.
You can have up to 4 items on the screen at once. Although I found it a bit tough to view. I think 3 will be the best option, since one ends up in the middle and larger, which you can set as what you find as most important, like the last lap for easy visibility at a glance.
And yea, it seems they are extremely popular with karting. I spent a lot of time on youtube trying to learn about the data set up side of this and most of the videos were karting guys. Then a few car guys and even a couple drove channels. NO motorcycle people, not a one!