If I'm working exact locations, I'll sit on a bucket and be closer to DD hitting. If I want to simulate the variance of actual pitches I'll stand. Since I have a ball coach radar, DD will radar me and we'll figure out what distance to throw from to simulate the probable pitching speed for the weekend (i.e. speed x .717 for 60mph, speed x .860 for 50mph). There's no need to get super fancy with all of the different speeds, generally just faster and slower. I do want to get her aware that there's a need to make adjustments for slower pitchers. Nothing is worse than seeing ill-timed swings because of slow pitching.