Hi Tracey - I live in the country where water is rare, I have never vacc'd to waste, only because it takes me over an hour to do the floor, so I'd have an epty pool then.
I keep the basket in, use the skimmer plate adapter and vac until the pressure change is about 6lbs - usually about the same time I can't fell much flow from the return.
Backwash, rinse clean both baskets and back to vacuuming. Never seen any adverse effects on my filter or equipment because of this.