Just pour on what you think you need. Then, set the filter over some paper towels in a drip pan and let any excess drain off overnight. Install the next day and more than likely you won't have any ATF dripping off the filter. Worked well on our K&N dirt bike filters to do it this way.
Just had a thought... tint 'n toner bottles from the beauty supply would work for applying that stuff. But I'll stick with the spray cans, it's just so quick and easy.