Regardless of the airplane, in my opinion, expo is a good thing. I usually start out at 20% and go from there. But, as mentioned, make sure you go in the direction that softens the initial throw. On some it's "negative" expo, and on others, it's "positive" expo. On those that have graphs, it should look like the below. This is just an example, but shows what expo, or exponential, looks like. In this case, I would call this "negative" exponential, however some may call it positive. Half empty.. half full... whatever.

CGr.