When in doubt, lower the weight
Shannoncorrin, Wadejen, Cab128 and other readers:
I certainly do not lift heavy, so I do not know much about spotting. But I am jumping in here just to mention a true story that happened in Toronto during the 1980s. A woman bodybuilder, exercizing at home alone, attempted to bench press 135lbs. The bar slipped from her hands, and dropped onto her neck, killing her.
So this could be a problem with 6-8 reps at 85% 1RM, for those who lift heavy. What I would suggest for those who have high 1RMs would be to lower the weight and do more reps for Meso3. This probably would also hold true for bb sqats and bb lunges -- for those who do heavy weights.
I might add that, with nearly all of Cathe's strength tapes (I have them all), the emphasis is on many reps with doable(safe) poundages. But as is discussed on this thread, the Meso 3 series might pose a problem for some -- with 6-8 reps -- without a spotter.
The reason for doing 10 reps, when figuring out the 1RMs, is to avoid this problem. A good idea, since many people on this forum have fairly high 1RMs on the bench press and squats.
-- David