cMotionTrail.mel 1.4.0 for Maya (maya script)

Hey mister ! I love your script but unfortunatly, like all other motionTrail utility, it is very hard to use when have many frames to handle (my shot is 400 frames !) I did an expression like that to update the frame range : motionTrail1.startTime=frame-10; motionTrail1.endTime=frame+10; it does work nice as long i use the 'update on demand' option (real time is good only for very simple scenes). but I have to create a new expression for each curve which is a pain and I also need to go back to my expression if I want to update my frame range. My dream would be to see that expression in your script with 2 sliders to see set how many frames before and after the current frame and have an update button next to it. Is it complex to do do that ?