OK. Time for some real climbing training. Let's start out on a Cat 4 and work up.
Fortunately, Burlington is at the bottom of the Niagara escarpment and a local road to the top is a cat 4. A nice 3k gradual climb. Since this was the first time up the climb I got into the small ring early and spun up in the mid 80 rpm. Not knowing what to expect, I wanted to be conservative and make sure I had some reserve. That was prescient. The first 10% grade hit about halfway up but the final 400m maxed out @ 21+% according to ridewithgps. I really had push to avoid coming to a complete stand still. Gasping for air, legs screaming, arms barely able to move the bike back and forth, I crest the hill. And this is a Cat 4??!!
The reward was worth it though. You hit the top and it immediately goes flat and then a descent down the escarpment back to the start of the climb. I was able to hit almost 63 kph on the way down on a very cracked, patched, potholed road.
I ended up completing 4 loops. The first two loops took about 22.5 minutes, the 3rd almost 24 minutes. The third time up I thought about calling it a day but I recovered well on the downhill and did one more in a little over 23. A comeback on the last lap. I was expecting each lap to be slower but I really hit the steep part of the hill hard and screamed down the descent to makeup almost a minute over lap 3.
At the end of the day my entire body knew I had ridden a hill or two. While the average speed was not that impressive (~25 kph), my goal was to consistently ride the hill, which I think I was relatively successful at. The fact that I did the hill 4x was also satisfying. Probably took the climbs a little too easy but that just means room for improvment.