250 watt scrog grow

OK...so my outdoor grow is coming to its climax and it is time to start thinking indoor. After a lot of research and contemplation I have decided to try doing a scrog grow. I know many people say that one should do a regualr indoor grow, or SOG before attempting a scrog, but I feel that I work better on the run so I am just going to go for it and deal with the consequences. Hopefully it works out.

After careful deliberation, I have come to the conclusion that a 250 watt setup, over a 3x2' screen will be sufficient to give me a decent yiled. And, if I mess up, then my 3 outdoor plants should supply me with enough to get by for a while.

Anyway, a 3'x2 ' scrog with a 250 watt hps will supply about 4500 lumens per sq ft (27000/6sqft). I know that 5000 lumens/sqft is optimal but I don't need my buds to be monsters even though I do want them to have very abundant lighting. I am going to set up a 50cfm exhaust fan on top of my grow box and probably the same cfm intake at the bottom of the box, directed up toward the lights (to bring cool air up from the shaded portion of the box.

So far, I have a bubbleberry and 2 GDP that I have just topped at about 4" and am waiting to start LST. These are two of the strains that I grew with outside, so I have an idea of how they grow and what nute mix worked well (outside anyway). I will use this as a base for indoor growing, starting with about 3/4 of the min dose I started with outside, and ending up with 3/4 dose of the max I ended up feeding with in my outdoor grow. During this time I will basically watch my plants and adjust this mix based on my observations.

I would like to know if my current plan of action seems like it is logical and sensible, or if I am missing something? Should I only use two of the plants instead of 3? when should I start flowering? I am a 215 patient that is just trying to set up a perpetual scrog grow ( I have clones that will be come mothers vegging under two 48" 2 40w bulb ballasts with a daylight bulb and a Kitchen and bath bulb in each one) to supply my own needs. If any is left over, it will just go to my coop to cover my expenses.

A confirmation that I am on the right track, or any constructive criticism, would be greatly appreciated. Please try to refrain from the typical "you need a 400w light for this grow", as I do not want to go that high in wattage to ease the potential heat problems and electricity bill expense. (but maybe these comments only occur on "rollitup", considering this forum seems to be filled with more helpful members than that site.) Honestly, I will reduce my screen size before I go up in wattage. I just wanted to state this straight out so that all the comments will be ones that will actually help me, and anyone else who reads this thread and is in the same mindset and boat as I am/will soon be.

As always, the advice is very much appreciated, and I am open to any and all suggestions (except using using higher wattage lights)