Before I get too far into a piece I am working on, I am trying in advance to work out some tuplets other than triplets and getting undesired results. I us the ; to get the popover to enter my information. If, for instance, I enter 5:4, I should get 5 quarter notes over a 4 quarter note duration, which works. When I enter a ratio 7:4, I am not getting seven quarter notes to the bar. I get whole notes tied to dotted halves. The groupings I am after are seven eighth notes grouped over 2 beats in 4/4 time and the other is five 1/16th notes beamed together over a duration of one beat in 4/4. Meanwhile, I will keep experimenting with it, hopefully with some results before the responses to this start to roll in.
Either make sure you have the note value corresponding to the unit you want to use for your tuplet chosen in the notes panel before you invoke the popover, or append the letter that corresponds to the note value you want to use as the unit for your tuplet, e.g. q for quarter note, e for eighth, h for half. The input method is described in the documentation here: