I would forget CO2 enhancement for a bit, at least. There truly is a large learning curve to this hobby. Learn the basics. There is more to CO2 than just sticking a generator in the space.
I believe that you will find yourself underlit with 1200W in a 200 x 200cm space. You are talking about 43 sq ft (if I did my cm to inches to feet conversions right?) A space that is 43 sq ft requires an absolute minimum of 215,000 lumens. Two 600W are going to be 180,000 max, depending on the bulb you use...so quite a bit short. I recommend either going to a smaller tent or going with 2 1000W rather than 2 600W. Your yield is directly related to your yield. And underlit spaces produce willowy plants with fewer bud sites and light airy bud.
I know that people always say that soil is more forgiving, but hydro has some benefits, IMO. Part of what I like about hydro is that the plants react very quickly to any changes you make...good or bad. Proper pH and monitoring of your ppms levels is critical with hydro. I believe that you use more nutrients if you do regular res changes with hydro than with soil. You may see a bit better vegetative growth with hydro, but flowering is the same. I have never found any organic nutrients that work well with hydro, so organic and hydro don't really go together. Res temps have to be kept in check or you can develop root rot and other problems. Serious overnuting can kill a plant overnight. And like I mentioned before, proper pH and ppms are critical.
I also recommend starting out with good genetics. While some may believe that it is better to start with bagseed, that is such a crap shoot and growing takes so long that, IMO, it is well worth it to buy good genetics. If you have properly educated yourself and don't have unforeseeable/uncontrollable problems, even your first grow should be good.
Some will say not to start out with hydro, but I think, if you educate yourself properly that there is no reason that you cannot end up with a good harvest.
I think that one of the mistakes a lot of new growers make is going into this without understanding how complicated indoor growing can be and how much it can cost to set up a good space. Make sure that you know what is entailed--the life cycle of cannabis, the nutrient needs during the different phases of life, lighting and ventilation requirements, training techniques, growing methods and anything else that looks pertinent. The more you know and are able to utilize it, the better your grow will be.
You might want to start out a bit smaller and then work up. A lot of us that have been growing for a while and have the space set up separate veg and flowering spaces. This may be a better idea for you than having one large space. You can harvest every 2 months or so or have a perpetual harvest and harvest on any schedule you set up. Plants veg in one space, which can be smaller than the flowering space. When ready, they are moved to the flowering room and you start new plants or clones.
So, read, read, read so you do not mistakes. This includes both buying errors and growing errors. The buying errors can be as costly as the growing mistakes. It is probably a good idea to get the opinion of the masses here before you make purchases. Often someone can help you to make a purchase that is not going to do what you think it is or someone knows where to get the same thing for less. There are a lot of advantages to belonging to a forum like MP.