Hot take: a 20 year installer in Reno told me he never kneels on the pad, and my knees stopped aching in 3 weeks
He plants one knee on a scrap of 8 pound pad instead of the carpet pad itself, which keeps the pad from getting crushed under the seams you're about to seal, and after 14 years of sore knees I finally tried it on a 40 yard stretch last month, so has anyone else heard this one or am I late to the party?
Man, I wish I heard this 10 years ago. I keep a scrap of rebond pad in my truck just for that, fold it in half for extra height and it saves your knees and keeps the seam from getting mashed down before you glue it. Only thing I'd add is make sure the scrap is clean, a little grit under there will scratch up a vinyl plank faster than you'd think. That Reno guy knew what he was talking about.