yield depends on much more then just topping or not topping.
this is a skunk #1 vegged for 2 months, lst'd and topped, in 3 gal bag. Under semi-ideal conditions.
I'd expect 3-5 oz's thats without co2.
growing this plant, I know that topped is a better way to go, lsting also helps.
yield depends on much much more then just those two factors.