never sweep the front leg. Sow gerk is one of the most usefull apps in my CLF arsenal. I think I can safely say, once I have lined my oponent up correctly (which isnt difficult) i can sweep just about every one . If someone is standing in a diu ma type stance or a one leg stance, he does half the work for me
in our siu ping kuen there is a move where you step from sei ping ma back into a gong ma. its used as a sweep too, pretty easy, effective and very common to get into when you are in a fight.
****, today im in such a mood to go spar with someone . pitty is summer holiday now, and our school is closed for the holiday. wish i could email myself over to the usa or some place