Proposal to Garmin is to improve track run mode to be able to select other type of track lengths as well - for example 200 (for indoor), 250, 300.
Understand there is some logic built into watch based on understanding how 400m track looks like but believe same can be done for other tracks as well. So there should be some pre-defined values and not let add user to set manually track length.
Another proposal is to make possible to change lane number during the workout.
It is normal that warm-up is done on line 6 or 7 or even 8 but when running interval you are doing it on line 1.
As-is only option is that you create multiple trainings, can't have one training session and you have to change lane number from truck run settings. It's not too easy process to follow.