I would like the option to calculate NGP using hrTSS. Using rTSS to derive NGP is inadequate for trails or variable terrain.

I'm a trail/ultra runner and am new to TP, though not new to tracking/analyzing data. I recently discovered that you can't assess NGP on a run unless you use rTSS. Using a pace-based threshold for trail running is entirely inadequate. My threshold pace would vary considerably depending on a huge variety of factors; steepness, terrain under foot, condition of the trail, heat/humidity/weather, etc. For example, if my threshold pace on a flat paved road is x'xx/mi, but I want to do threshold intervals on a steep uphill trail (say a 30% grade), how could I ever attain that x'xx/mi pace on that steep grade while staying below threshold? My heart rate would reflect the effort, but my pace would fall well short of the x'xx/mi set as my "threshold pace"...and therefore my NGP wouldn't be close to accurate. Strava seems to have figured this out quite well with their GAP metric. I had heard about NGP before joining TP Premium last month, but am disappointed to find that NGP is not as useable as Strava's GAP for a trail runner. Unless I've got something wrong here with my understanding of the process. Any other trail runners out there experience this same issue, or find a way to get around it?

This is similar to the idea described in the "Improve accuracy of NGP on hills" thread on here, which has been marked as completed. Figured I'd revive the topic. Thanks for reading my essay!