That is probably the most impressive lift of all time. Kirk Karwaski is probably the best pure squatter of all time, and he would likely not be able to squat 7 plates for 10, and definitely not without breaking a sweat.
That would probably translate to around 1,300lb WPO squat. Luke is the strongest man who ever lived!
kirk squatted 1000 for 2. i'm sure he could get 675 for 10. tom platz could do 585 for at least 15 in his prime. JP fux is on video squatting 675 for somewhere around 6 reps.
assuming if you will that luke doesn't go to the kind of depth kirk did, 675 for 10 is believable given how enormous the guy is. and how you would say a 675x10 squat translates into a 1300 pound single is beyond me. where in the world does doing 10 reps with something mean your single is DOUBLE that?

for another example, andy bolton pulled 800 for 8 raw a while back, his single is 1003. that should give you an idea.