Mickey,

Well if you leave the torch on unnecessarily you'll shorten the life of you consumables..you probably already know that, just thought I'd mention it just as an FYI. Are you worried about hurting the machine?

I think what I would do is get a straight edge. I think your unit should have a pilot arc so the flame/arc stays lit/burning.?? Correct me if I'm wrong. Take your straight edge and clamp it at both ends, then take your torch using one hand to slide on the straight edge and your other hand to switch and hold the torch. Just set your height above your expanded metal and just leave the trigger squeezed. Just drag it toward yourself using a moderate speed while cutting then quick hops between the gaps.

Hope this helps you or at least gives you a starter idea ,
ILP