Didn't really wanted to post here, but some posts here are missleading or not clear, so about modifiers in CtB:
In CtB modifiers are greatly related to approach rate and a bit to circle size, I'll describe how most players use them here (keep in mind that each player is different and I'm trying to get a general overview of how mods are used in most maps)
- Hidden:
- AR<=7: HD makes the map way harder to play and should deserve a significant bonus, sadly most AR<=7 maps are easy maps (especially converted ones).
- AR=8: HD start to be less annoying on most maps. It still deserve a significant bonus on hardest AR=8 maps but at this point a huge amount of players can easily play AR=8 maps with HD.
- AR=9: Most players will use HD on AR=9 maps cause it doesn't disturb them anymore, some players says that it actually help them to have HD in AR=9 maps. Most of those plays doesn't deserve any bonuses, however some AR=9 maps using complicated stream patterns would still be awarded by a bonus (the idea here is that HD on AR=9 helps a bit for huge jumps and make precise patterns like streams a bit more difficult)
- AR>=10: I think only 10-20 players in the world plays AR>=10 without HD. A HUGE amount of players will say that it's easier to play AR>=10 with HD. I don't think any bonuses should be deserved for most of those HD plays (Actually a malus would fit better but I think it's a bad idea since it will screw the map rankings)
- Flashlight:
- Most of FL plays are done in AR=8 mainly on stream maps. I don't know this mode well enough to say more about it.
- Hardrock:
- AR<7: HR would deserve a little bonus depending on the map difficulty.
- AR=7: HR start to have a huge effect on many players, clearly deserve a bonus but nothing really huge since most of those maps are pretty easy.
- AR>=8: Everything over this point should deserve a nice bonus depending on the map difficulty.
- Double Time:
- AR<=7: DT would deserve a little bonus depending on the map difficulty.
- AR=8: Here is the most complicated part. AR=8 maps with many 1/2-1/4 movements and/or really huge jumps and hyperdashes are most likely being harder with DT than with HR. However most AR=8 maps are still easier with DT than HR due to how they're mapped.
- AR=9: I actually don't know any AR=9 map being easier with HR than DT, those FC are rare, even clearing AR=9 maps with DT is challenging for most players. The FC's should get a significant reward since it shows the player capability of reading high speed AR, memorization and ryuuta control.
- AR>9: I don't know any player capable of reading this speed.
For mode combination in most case HR and DT adapt the AR for the other two modes (For example if you use DT and HD on AR=8 the description of AR8 DT is valid but for the HD part you'll have to use the description of AR9 since AR8+DT speed is closer to AR9 than AR8). A specific case exist with FL+HD where the player almost have to learn the entire map wich is obviously a really great challenge.
I don't know enough about Half Time and Easy modes. Only thing I can say here is that EZ+HD on hard maps are really challenging and should maybe work the same way of the other modifiers.
My thoughts about accuarcy in CtB: This is just a % of completion of the map, nothing related to the other game mode. Droplets are easy to miss and they don't even have hitsounds so you basically don't know when you're missing them. Any bonus or malus related to droplet misses should have a minor weight in the total calculation. However Zirox's calculation sounds good to detect on wich maps it could be more or less weighted.
Spinning well isn't given to all players and I think a fair calculation could be "more bananas = more weight in the global calculation". Being myself bad at spinning I think it's part of the CtB skills and this should be well rewarded in the global calculation.