HRP , I am not trying to knock the way you do things , its why I said if it works for you by all means do it .
There is No argument from me
I Have been painting 30 years and have a excellent rep myself .
Finding a system that works for you and sticking with it , as long as there are no paint problems is what a painter strives for . The switching of this new item , and switching to that new product , a person never finds a system that works and makes you money , or good results .
I have had helpers that always ask me why I dont try some of all these latest new fangeled products , I tell them I have a fool proof method , use less products , and achieve excellent work ! I will switch when I think a product will save me time , not because everyone else is using it !

I just find that the finer the sand scratched the less wear and tear on the old body for blocking
My back , shoulders and hands ( carpel ) have set in . Knees are going now

I can rip the paint off in almost the same amount of time using a MUD HOG with 80 grit , its why I question the grinder and 36 or 40 is all . I will then go over it with 150 on a mud hog , and have a nice smooth surface .

Spray