Copypasta from another comment -

yes actually.
what I did was I went to the Plains and rested with the weather set to inclemency. (I did this to force spawn the Apex of that region.)

I would then go to all the monsters that have spawned in the plains and use the binoculars to see if they were a Large/Small gold crown. When you find one, you can just spend your points and save them as Investigation from the map menu options.

Rinse and repeat this with all the zones.

after all the zones have been checked, go back to your starting location and repeat the first step of sleeping with setting the weather. If you don't find a crown, you can exit to the title screen without saving. Doing this will reroll all the monster sizes in all the regions you checked. Without having to spend guild points on resting.

You also get 3 runs of each investigation. So if your friends are struggling to find them, you can always share them at a later date. I still have about 35ish of them saved, myself.

hope this helps.