I don’t have a Port-A-Tree, but I do have DragTracker iPhone app. Here’s how I use it. I watch live events, pick a lane, and mimic the process until they both are staged, then focus and release on the practice tree. At first I was all over the place. I did this for over a year, while I was unable to race. To make it more realistic, I eventually only released once or twice an hour, just like later rounds. When I finally made it to the track, I was -.002 to .000 over 5 passes. Sounds anecdotal, but seeing the tree over 3 days felt like I had hundreds of seat time stages. YRMV. Oh, by the way, a good friend with a trackside parking space at CFR, got in trouble for practicing with a full size Port-A-Tree. lol