Ah thanks! Yes, I am planning a hill repeat workout and knowing this hill at 9% gradient and the Strava CR is at like 9:15 pace, I am planning to go for 11:00 or so pace. So when I put the ~1.5m interval, I am only asked to input % of threshold pace and obviously, that has no appreciation for hard this 11/mile will actually be (the CR is a pro runner). Because I use TSS as my #1 compliance priority, this will likely result in a yellow or orange for being too hard. I know I could go through the motions of calculating TSS manually given I know the gradient of this but since I have many hills to choose from around here, I was hoping for an easier way to have the planned TSS in these hill repeats.
Question: Do you use the structured workout pace to drive ALARMS on your watch? In other words, are you trying to have your watch tell you if you are running too fast/slow and beep at you in those cases?
Or...are you just trying to calculate the predicted TSS for the run assuming you run up/down at your target paces?
If you are just trying to calculate the predicted TSS (and are NOT going to use pace alarms)...then you can just work off of % flat-ground pace. TP will compute Normalized Graded pace after the fact in order to compute actual TSS...which is the same as "flat-ground pace", theoretically. I've done this in the past, by running the workout once...and then used the recorded data (NGP for each segment) to construct a TP workout that matches.
If you want alarms for going too hard/easy...then you'd have to switch to a HR based workout. Or...get a running power meter like a Stryde, and program based on running power instead.