I think watts and duration are going to be best here.
Here’s a little snippet from Nate from a TR AI post.
What about my TSS?
If you were at really high progression levels, your TSS was probably pretty high. There would be a down adjustment compared to what you’ll get now.
Frankly, I think we’re moving to a post-TSS world with this AI, but if you’d still like to use it, I would just be aware of the recalibration and know it will be more consistent going forward. But remember, even at the same FTP you’re going to get more TSS if you’re at a higher workout level (in general).
Let me know if this helps!