An assymetrical grip (“traditional grip”) promotes assymetrical thinking, as a German drummer interviewed in the latest Modern Drummer magazine points out. The simpler “matched” grip, in which left hand mirrors right, is often promoted for its very symmetry. This might be ok for eighth and sixteenth-note rhythms, but I dislike it for triplet-based feels.

Playing triplet-based rhythms with two hands can lead very naturally to polyrhythms. Play eighth-note triplets with alternating sticking: rlr lrl, etc.... Accent every other right, and you get Rlr lRl rlR lrl: three half-note triplets against a quarter-note rate.

I count out the 4 against 5 polyrhythm like this:

ONE two three four
ONE TWO three four
ONE two THREE four
ONE two three FOUR
ONE two three four

Tap with both hands on the first ONE, alternate hands after that (e.g. the left will tap all the subsequent ONES and the right the TWO, THREE, FOUR, or vice-versa)

This is easier than four measures of 5/8 time:

ONE two three four FIVE
ONE two three FOUR five
ONE two THREE four five
ONE TWO three four five

These polyrhythms are symmetrical: identical backwards and forwards in the spacing of the notes.