Hello, I believe the trick in keeping the number of lessons low is to find a good trade-off between new vocabs and reordering. I made a lengthier explanation on how I do this (shameless plug) but tl;dr: there is no point in rushing the kanjis in the first block as your bottleneck uniquely depends on how late you start and finish your second block. You can speedrun and still engage in the 0/0 streak challenge if you learn to use the scripts properly.