Some users may not be aware that you can view how a system would have performed at various teaser lines in addition to the system's record straight up.
Once you are done building your system, just click on the record in the top left corner. Each sport/bet type will show a corresponding set of teaser lines and the system's record for each one.
For example, the system above has covered at a 56.4% rate and has covered a six-point teaser 72% of the time. You can use these winning percentages to help calculate your expected value when betting on teasers.