N1s for sure I think are the best types of rounds as the "go-to". With then N0s thrown in.
The higher stuff should be more sporadic in my opinion
1. These types of rounds are readily available on other servers already at great frequency (N0/N1 rounds are not).
2. High start rounds are less interesting, the whole building phase is nullified and it becomes often a barb-nobling, AM fest. Bit dull if this happens all the time, but sure a nice change once in a while.
Two things from me,
1) If we got more warning for rounds people might be able to play more ( I know this takes more time from the mods tho, so no worries if this isn't always possible - I know you do your best).
2) If weekends can be populated with fast, short rounds that is much better. The longer rounds basically mean the only people who can play (properly) are those free the entirety of Saturday. If someone has something Saturday morning, or Saturday afternoon, they miss speed the whole day rather than being able to play the couple of rounds that suit.