I'm going to guess that most robots can hang quite a bit off the edge. That being said balancing with 2 longs is always harder than 1 long. Personal experience. GTR East
QF1-2 1075 and 4307, no balancer with 2 long bots, however 4307 was not even close to max and it went smoothly.
Northville QF's SF's and F's 5 triples with 2 wides, 67 and 3656, using 67's arm... Extremely smooth. Troy finals 2, 217(long) and 2604 attempted to triple, we failed to do so. MSC 2054 (long) and 245
it worked but wasn't pretty and we failed to do this twice. Finally
Newton 118 and 2194 both wide, utilizing 118's stinger and our fangs, 4-6 with 2 driver errors keeping us from 6-6 (QF 1-1 half of us were going for a double).
Experience has shown me that our 19" needed on the bridge is a little more then that depending on the speed of a balancer as the rotational momentum of the robot tips it down and sometimes off the bridge (problem solved by using 2 balancers).