They were posted on here a good year and a half ago. The search function was changed and is weak, so it will probably be tough to find, but someone who has it bookmarked might be able to repost. It showed them @ like 5am in the morning doing drills and then sprints up what looked like a dirt or gravel road (and Asafa showed up late, half asleep and understandably so). There was another that showed him doing sled sprints and some grass tempo 300s in there as well.
But yeah, it is hard to gauge exactly. I mean a very relaxed start and on nicer, but thicker grass is going to make you run a bit slower than your best. Assuming he is running on the same grass track though 37s for Asafa would be well above 85% (assuming the same type of effort was given at the start while the 37s may very well have significantly easier starts). I mean, it certainly isn’t high quality SE, but there is going to be more than just a recovery effect–there should be a significant training effect.
On top of that, grass does let you handle substantially higher vol bc of the lack of lower leg issues and overall stress.
And again, Asafa has run 45.x during the late winter/early spring in Australia and Bolt ran 44low early this year, so while those times are not equivalent to their 100s or 200s, it is certainly beyond a level of just “showing up for the fans” in my eyes.