Here's a general rule I try to follow when tonguing...
Softer notes = more ping at the beginning of the note
Loud notes = less ping
For example, in Hungarian March, I want to let the air do the work on that run. I feel as if I'm using very little tongue since there's so much air.
On softer notes like, maybe, the scherzo from Tchaik. 4, I use more "ping" or "pop" at the front of the note.
Maybe I'm wrong here but it seems to work...
