Another observation - I threw in LMR Functional Upper & Lower with balance bonuses into my custom XTrain rotation a couple weeks in. I mostly did it as I was suspecting I may need a little extra break/recovery as I get back up to speed with the more physically demanding XTrain rotation.
I found that both presented a nice change-up/challenge and found myself surprised to be feeling a little challenged by them despite the more intense workouts from the previous couple weeks.
With that knowledge, I'm thinking I'll throw in LMR FU/FL/TB as occasional one-offs in the midst of a more demanding rotation. I don't think I'll suffer any loss from doing so. They're added recovery (maybe consider them de-load workouts), and for sure balance practice so long as I include the balance disc bonuses.
I maintain I won't ever use them exclusively for weeks and weeks, though, as that will set me back, especially my cardio.
Thankfully my cardio capacity is bouncing back pretty quickly. I can only credit that to plenty of years of Cathe cardio under my belt.