I think I Barliman Butterburred it: Start off at as low a trajectory as possible, and shoot the cone upward so the bulk of it reaches high orbit and starts to decay. That'll cross the most pathse. Bonus: Find out what the prevalent direction of sattelites is and try to go opposite to maximize delta v and passes-per-orbit.

If it explodes as an orb, you'll lose most of your material to space or the atmosphere. Probably want a shrapnel cone in line with the orbit, maybe angled a little spaceward so more material gets into higher orbit to eventually decay.