Look at it this way: 100 items a month when WK has over 8000 items (2k kanji, 6k vocab, and then some radicals) would take you roughly seven years to complete. My guess is you’d like to go faster than that, especially since you’ll want to add in at least grammar study at some point as well.
So yeah see if speeding up works for you, and only slow down when you feel overwhelmed. The easiest way to control the pace is to not do new lessons until you’re comfortable with your review load. So once you hit a new level and 0 lessons jumps to 100 or whatever, maybe just ignore the lessons for a couple days until you’ve Guru’d most of your existing reviews. That way you won’t have too much at once.
Don’t get me wrong, “too much” is subjective and it’s still going to keep you quite busy. According to the WK Stats Site I’ve answered 45,994 review questions in 187 days, which is 245 per day. Although cut that in half since it’s separating meaning + reading, but even then it’s still about 123 radicals/kanji/vocab coming back for review per day on average.
But if you go closer to two weeks per level, you should maybe see closer to 80 items reviewed per day. Granted, this depends in part on your accuracy. More errors = more items stuck on lower levels = more frequent reviews than the numbers I’ve cited here.