I noticed during three periods of trials that the rocket launched sooner later on in the day. In the morning the rocket consistently launched after 5 pumps with the "low" washer and 7-8 pumps with the "high" washer. By the afternoon it launched after barely 4 pumps with the "low" and 5-6 with the "high." It was a warm day so temperature definitely played a role. Looking at archived temperature data for our area it was about 82 degrees for the first period's data, 90 degrees for the second and 97 degrees for the third. If you look at the consolidated data for all three periods you can see that the maximum heights and initial velocities decrease as the day went on.
My last period did get a chance to try the "super" washer. Now I wish I had tried it in the morning for comparison when it was (relatively) colder.
There are lots and lots of things you can do with this rocket. There is an additional set of wood angled blocks for consistent angled shots you can purchase.