I have found that ginger (which interacts with 5HT-3) helps nausea for Rue/Mushroom trips and have not noticed a difference in visuals. I have felt calmer and more bliss and the trip is still strong, but the calmness that may be because I added lemon balm which can calm the nerves. Or it could be that I enjoy herbs and tea and they are helping with my set and setting. Unfortunately I combine several herbs together and have not done a systematic study of individual effects.
I typically grind the rue into capsules (3g). An hour later I take a magic tea which combines mushroom and herbal hot infusion.

For me, ginger slightly diminishes Visuals. It is very subtle, but definately noticeable.

Anticholinergics tend to do the opposite.