[Imp]

If you want bigger booby trap without making a new larger weapon have you tried modifying it.
1) put another booby trap in weapon slot 2, more chance of a kill same blast radius?
2) swap the booby trap weapon for something bigger, say a satchel charge.

I am assuming the unit class is what dictates the behaviour so changing the weapon it should still go off.

The more weapon slots you use (if they all fire) the greater the chance of the unit being hit & I would expect greater suppresion.