That's some good advice! Thanks! Yeah, I only managed to catch one tornado as it was roping out in Wray, CO after dodging baseball sized hail. I think I was only able to catch it because I had come up behind it. Most other storms, I insisted on being in front to photograph the gust front and shelf cloud. I didn't consciously try to have a take away point from each chase but I think the majority of my chases were "successful" in that I found a storm, filled up an SD card and didn't get hail damage, minus a broken window from a microburst in Sharon Springs, KS.
Though, as you were describing with a realistic chase goal, I did try to focus on that. I figure that 99% of storms I chase won't produce tornadoes and most aren't even surface-based. Last season, I just tried to chase whatever popped up, just to start getting familiar with different cell structures and start to develop a system for navigating, chasing, setting up my cameras, safety, etc. I like your idea of having specific goals for each chase though. Got me thinking about starting a chase log and writing down my goals, observations, and learned lessons.