I do it the same way for a stand still, walk, and jog - I just use my left spur for the right lead and my right spur for the left lead.
I'm not sure what you mean about asking for a lead from a lope.
For a flying change (assume she's going from the left lead to the right), I hold my left spur on her around the bottom of the circle and when I get to the middle I switch spurs, move her shoulder over with my left rein, and move my seat slightly to the right. She's still learning these, which is why I do so much. Eventually I'll just press my right spur into her and slightly use my left rein to tell her I want to change directions and not counter canter.
^^ They don't want the horse to pick up the habit of trotting any strides between walk and lope. That is a major fault in a reining class. If you are wanting to know how to cue for your guys lope, I would suggest working with the trainer so that you know what cue he was taught.