now). cut that coat not to make it perfect, but to get the basic shape and filling you need as a base for the skim coat. you can cut it with 36 40 or 80 depending on how big the area you are working is. in other words, if you can cut it fast with only 80 then do it. but i would say that this would be limited to an application that is no larger than about 8 inches.
if you happen to have a few high spots, see if you can tap them down. if you have a few low spots add a bit more filler to only those 