I'm able to set clip lengths to vague times by dragging clip size with the mouse but it's virtually impossible to set them to a specific, frame-accurate length this way. It would be easier and faster, if there were some way to simply enter the running time desired for a clip in minutes, seconds, and frames. Perhaps by getting some kind of context menu from right-clicking on the clip.

As an example, I was trying to make a video of a Pecha Kucha talk by importing 20 jpegs and making each a 20 second clip. Dragging stuff on the timeline gets me clips that are 19 seconds and 15 frames or 20 seconds and 2 frames, etc. but it's very difficult and tedious work to edit frame accurately.