Ready to add CO2. Now what?

I have been putting this off because I'm going to have to do some major rework on my ventalation set ups, but I have decided that it is time to add CO2.

I know about light and ventaltion schedules, PPM and most of that stuff. What I would like input on is what you guys recommend for the actual method of injection. I am leaning toward a CO2 generator, but I don't know. Maybe I should just try a home made simple thing, but I'm afraid these don't do much. How about a tank? What are the pros and cons?

I have a walk in closet. On the left is mother plants and veg. On the right is clone and flower. The flower area is about 3'x3' by 8' tall. I have great success with the veg stage right now and don't want to bother changing it. They grow almost too fast for my schedule. Where I want the enrichment is in my flower area only. I don't have a lot of room left in there for tanks or other stuff, but I suppose I could mount a tank up near the ceiling. I think I could probably just hang a generator on the wall in the flower compartment.

Could I get by with a low end generator for such a small area? Or do you get what you pay for, and I shold by the best one?

If anybody does the home made CO2, how do you do it, and do you really notice a difference? Have you measured PPM or anything?