Hey @PB234, I usually go by stats and crowd consensus, especially when enough reliable people report the same thing. This game has so many variables, and with random updates, things change often. My original tips post is pretty outdated now, though I’m working on updating it. It’s like ‘Who Wants to Be a Millionaire’ - the ‘audience’ is usually correct 
plus some sort of fuzzy logic you need to apply along with some maths lol.
For example, I’m now getting reports that the Charoite (purple) and Sapphire (blue) dragonets might be appearing in both Bust Tier 5 and Bust Tier 6 parties. The chance seems different now that the offer is indefinite. I’m not sure if it’s tied to the host, their city size, or if they already have a dragonet or that specific dragonet. I do know the last 5 of my 10x unicorn parties (Tier 7) all yielded a Jet dragonet according to the attendees. But, I suppose it doesn’t matter much yet since it’s not that much harder to bust Tier 6 parties, and so far, only one host has mentioned the attendees getting both Charoite and Sapphire dragonets in one party.
Hey @River_girl, regarding your question about TB prizes:
Your city has prize tiers that work with random multipliers from 0.5x up to 10x for the TBs (Treasure Boxes). New buildings, especially with the HMP (Honeymoon Period), give a bigger boost to your TB tier. Even in a maxed-out city, I’ve noticed that adding new buildings still boosts the TB on average.
However, be careful with when you add them. If you add new buildings between 6 PM and 8 PM Pacific Time , or around 10 PM to 11:59 AM , you might get caught in some sort of tier reset or prize downgrade.
Please take a look at this discussion from this post down regarding the treasure box - Tips and Tricks for Beginners and Veterans - #80 by Night_Guy