If you don't want to stress them at all just bend them down into the right shape for max light penetration....if you dont know how a strain will react to FIM or topping I wouldn't do it.

Have any shown sex yet? Should be soon....look very close on the nodes.

They look really good by the way....I only use a 80watt for veg mine are way more lanky than yours then on to the 600 digital HPS for flower.

Nut sure if your doing any bene. bacteria but your res should not smell bad....add some hydrogen peroxide to clear it up. You dont want to pump festering nutes to your plants, its bad news.

Hydrogen peroxide will kill good and bad bacteria, mostly bad since most good bacteria are aerobic but add enough and you kill them all. try 8ml 3% H2O2 per gallon....do it for a few days and see how they react, you might be pleasantly surprised.