Fill (chosen) voices in a selection with (chosen) tuplet

This plugin fills your choice of voices in a selection with your choice of a tuplet. Adjust the variables (startVoice, endVoice, measure, rationum, ratiodenom, tupdur) (right after the onRun statement) accordingly in a plain text editor.
Internal voices 2-4 do not have prefilled segments, so some workaround is required. First each measure of each voice gets a whole note rest. Then they first get a rest of the required length, and then the tuplet. This is (as far as I gather) because addtuplet does not advance the cursor (and leaves it in limbo) while addRest (and addnote) advance the cursor, thereby creating the next needed segment.
The code contains the recommended changes for MU4 (h/t Jojo Schmitz). It may run in MU4 but I cannot vouch for it, as I am on MU3.6