second topping?!?

Don't do this stuff whimsically. Start with a target of X colas per sq ft, and then make it happen in a systematic way... dividing growth as evenly as possible so none have a distinct advantage over the others. this will create even distirbution of yield and make it nearly impossible to over-crowd your canopy. It'll also reduce waste by getting to that end goal with the least amount of wasted time and resources. 2.5-3 colas per sq ft is all you need. Beyond that you are not increasing yield. Just spreading it out across smaller buds. There's no circumventing the grams per sq ft you can produce relative to ambient CO2 and appropriate DLI. With seeds, shoot for 50g/sq ft. With clones of a monster yielding plant you can push up to 70g/sq ft. This is relative to ambient CO2 levels. Supplemental CO2 might be able to get up near 100g/sq ft in ideal climate and maxing out DLI relative to that added CO2. DLI dictates yield. After that it's simply having 'enough' colas.. not 'more' colas.