Use incendiary grenades since they stack the highest scorch. Everyone loves the new solar but the dot doesn't stack. Use a weapon that rams scorch down their throat like skyburners, jotunn with catalyst, mini tool, or staccato both with incandescent. Once incendiary explodes and everyone is smoking use incinerator snap and they ignite. Whatever is still alive shoot with the weapon to spread scorch. Obviously ignite works better on higher health targets as usually burns and snaps kill red bars.