How to effectively/quickly level Illumina routes?

I completed the main story to New Pokemon Snap, and I am going back to the previous routes and maxing out each one for 100% completion. While time consuming, the standard day/night routes are fairly straight forward to max out due to how expedition points are calculated.

However, because of the way expedition points are calculated, I am having a difficult timing gaining adequate expedition points in the Illumina routes. These routes will have very few Pokemon to take pictures of, so the amount of experience you can obtain is limited. The last three attempts at the Meganium route, I received 0 expedition points with having 29,000 left to hit the next level (or max?)

Is there a special trick to gain experience and level up Illumina routes?