I would just pick one of the preset tuners parameters they request for logging tunes. They usually have everything needed (pretty much boost and timing are the main drivers though).
In regards to Dragy, I guess whatever you are comfortable doing. Try and avoid gears/rpm where you induce traction issues to rule that variable out. Make sure all have the same spark reduction value set. DSG car? Do you get traction at 40? 50? I wouldn't brake boost, just hold rpm at set mph and nail it. Say 45 as an example. Set Dragy to custom and have it log 50-60, 60-70, 70-80, 80-90 and even better if you want to go into 4th but again don't want you to get busted. Try and pick a flat road (it won't show slope on custom but doesn't matter if same one is use for consistency). Try and let the car cool down between runs so it doesn't heat soak. 3 per tune to ensure no variability.