We top leaving two nodes. We then top the two shoots that jump up from the top node afterward, leaving a node on each. After that second topping, the two shoots from the bottom node reach canopy level, provided they received adequate light. When the plants go into flowering, they form a total of 6 colas; two stalks from each of the two topped shoots and two from the bottom node.
Feedings don't need to relate to the trimmings. During veg, you constantly give them vegging nutrients; before, during and after trimmings.
How much time they've been growing is irrelevant. It's the size that matters for trimming; how many nodes, leaves, etc.