But why not let the Quantize Setup dialog do all that for you? (it’s really very easy 
)…
Let’s take two examples, using quintolets…
Open the Quantize Panel (or the Quantize pane in the MIDi Editor’s Inspector)
-
5 beats in a bar of 4/4…
Set Grid to “1/1”
Set Tuplet to “5”
Done!
-
Quarter-note subdivided into quintolets…
Set Grid to “1/4”
Set Tuplet to “5”
Done!
… and you can even use the “Randomize” function in that same panel .