Brilliant work! I have similarly spent many hours pacing around a playing field just like that.
I saw your evidence about not using bow-offset at the start, and it surprises me, as it is coded to do that and it does for me! I’ll have to do some more work to see what’s happening.
Regarding no layline alert for the top mark: you were assuming that it would automatically start navigating to the top mark after rounding the bottom mark. A very good assumption, but unfortunately not one that I have incorporated in the code. It didn’t report the layline because you hadn’t explicitly told it it to navigate back to the top mark. You have to go to the mark menu screen and select the mark to navigate to in order to get it layline alerts. A good thought for an enhancement.
Your comments about how long it takes to report tack analysis and mark creation are fair while pacing round a field, but it has to find you on a new stable course before it can determine you’ve tacked or rounded a mark. For that it needs at least 30 seconds of data on the new course before it can determine that it is a new stable course.