If you do a Match frame it should bring that clip into the Source Monitor and you will be able to see the range of the used part of the clip..
I would have thought the precision of the EDL would have been ideal and convenient for what you are doing.
Check the metadata settings and see if you can show a column that suits your purpose.for the used clips.
FWIW. there is a function to display frames but I do not know if that extends to the source monitor display.
You might need a TC to frames Calculator.