surround fusion coils with boxes suchs as red/blu columns on sandbox and only have them blow up from one way which wouldnt hurt those behind and blow up in front
I attempted conveyer belts after i saw pallet parade and its physicly impossible with grav lifts, not enough power and mancannos to fast (with indesructable movables btw) plus respawn takes piss
Nearly every exploding object in H2 had nearly the same blast radius from what I remember. Using Regular old Fusion Coils won't kill the game play, it's only a minor aesthetic touch. Plus judging from the placement of the plasma batteries in that pic of Colossus using two-four fusion coils as a substitute would set off the whole belt ending in epic lag. Conclusion; one fusion coil seems fitting.