Topping?

You can top with 1 node there’s no cut and dry rules. Given its hydro it will recover quickly. Depends what you’re looking for as an end result. Just one topping and LST from there or multi topping? I usually now top and leave 2 nodes ( 4 branches) and LST those out then top again and possibly one more time. Depends how long I wanna Veg. There’s plenty of strategies just work backwards from what you’re hoping to achieve. PS- I’d try to fill that net cup all the way with hydroton/pebbles. Any light leaking into the res is trouble

how many primary branches do you want? how big will it get? these things matter. when counting, i'd exclude the lowest 2 branches. they tend to make trash buds even if kept at same level/height. most of your plants have some axillary growth already starting -- this is somethign i wait to see before thinking about topping, in addition to how many branches i want to fill a space. i don't want little axillary buds with zero growth. i want them at least starting to grow out. doesn't have to be major growth, just not a bud. (not a flower, they are called axillary buds at growth nodes that form branches) work backward from intended size to fill your space... answer picks itself.