I agree with more plants in a SOG equals more to worry about and can be a pain to water unless your doing hydro or have a watering system set up. It seems like P takes his plants out of his grow to water as well from the pics? Which is going to be hard to do as they get bigger and wouldn't really work well for either system. Its best if you can keep them in their environment and not move them to much as they get bigger and in flower. What you should do P is look at people's grow journals on here that are using your same type of light. Will give you a great idea of how to get the most out of your light. The issue you have is penetration...lol that sounds funny
The light you have will not be as effective with tall plants. So you should look at techniques like LST, topping, Fim...those would work good for creating bushier plants with an even canopy so you can have more top bud sites close to the light. Those techniques work great when you put a screen down and scrog. You will have less plants that cover the same area and produce the same or more buds (in theory) then having more plants in a SOG. The SOG works well from clone with little or no-veg time and you have more plants that yield less but make up for it with qty and shorter turnaround times.
I topped my current grow and did some late lst to open the canopy to let the lower part catch up and create an even canopy. I have two plants that cover a 2'x3' area and should produce as much as four if I grew them without doing any type of training in the same area....based on me keeping them the same height and veg times. For me it comes down to space of grow area and type of light (400 HPS) the number of plants doesn't matter as much because they will fill the space regardless and my light can only do so much (3'x3' area and 3' deep penetration. I added the net right before flower to help open the canopy and support the branches as the buds bulk up and get heavy.