What is an effective way to get all gold crowns?

I'm trying to get every achievement before the release of Iceborne on PC. And, I'm sure you guessed it, the only ones left on my list are "Miniature Crown Master" and "Giant Crown Master".

I've gotten a fair chunk of gold crowns so far (both small and big) and doing the event quests (Coral Waltz, Deep Green Blues...) aren't really worth it anymore.

I've heard that you need investigations with at least one silver and one gold reward to have a chance to spawn a gold crown monster. Is it true? Are there any more investigation parameters I should be on the look out for?

Basically, is there any way I can manually filter my investigations to find ones that have a (higher) chance of gold crowns?

Solution 1:

doing the event quests (Coral Waltz, Deep Green Blues...) aren't really worth it anymore.

Those event quests offer the highest chances of gold crowns outside of quests with fixed sizes. Keep doing those quests.

For monsters not available in those quests, investigations in general will offer a chance of finding a giant or minature size monster, where optional quests usually don't. In the majority of assigned and optional quests, it is impossible to find a giant or minature size monster.

Investigations with at least one silver and gold reward do seem to increase the odds of crown monsters, but specifics are hard to find given the many variables and the limited number of times investigations can be posted.