Using preservative for dry hay

I figure this is a good place to ask and discuss this topic. After last year's rainy season, I have been looking into different forms of preservative to help make dry hay. It is not a cure all by any means, but might help get some more in a bale before the next rain.

What do you guys use? Granular or liquid? If so what brand do you like?

I would need to get an applicator, I am leaning towards the granular dry type, putting a box on the hitch of the baler. Thoughts please..

Using preservative for dry hay