I've just had a look at Mary's #10. I've never seen anything like that. Is it valid notation? I thought a triplet was 3 notes of the same type in the time of 2.
I think if I was trying to handle it in abc, my own choice would be to just give a straight triplet and add a N: entry to explain what I'd done and why.
If I was using MIDI as the main purpose (something to listen to), I would need to know how it sounded. I would then adjust lengths to suit that and forget any thoughts as to how it looked.
Not saying any of this is right, just giving what I think I would do with 2 very different objectives in mind.