I had a new look at my lessons per day, and found that my average for the last monthish was about 19 per day. I expect this number to go down as I get more and more items in my queue. Probably gonna end up around doing around 10~15 per day, I suspect. I follow the lesson cap strictly, so my review count will remain the same per day (I get around 120 reviews per day, which is enough. Truly.) pretty much anyway, but my number of lessons per day will go down, as I get tougher/less familiar kanji.
The spikes probably coincide with my levels up, at which I do all radicals at once.