Ya those hydro guys are quite the salesman. They will push those products on ya HARD! Just gotta learn to read the labels, as you can call them on their shit sometimes. There's plenty of products out there for less that have the same forumlas and sometimes even more strength to mix more gallons than the equivelant nute with a more expensive brand. I say look to as many raw, organic sources you can find, or at the least, goto your nursery & home dep/lowes gardening depts and see what's out there that can be used at lower prices before running into the hydro shop.
The SWEET product is directed for flowering, don't get me wrong, but it is best to feed your plants carbs all the way from start to finisih. The reason for this, is that quality soil has living bacteria in it. This works in tandem with your roots as it colonizes throughout, but like any living organism, requires some sort of food. This is where the carbs are hands. They feed on these carbs, and the byproduct will be a release of natural vitamins, aminos, increased nutrient uptake, and much more that can really help your plant. It's not ALL about feeding carbs in there for your plant to absorb. At the rate roots absorb carbs, one could never expect such a thing. It's all about feeding the beneficial bacteria in the soil, and then there's gonna be some leftover for your roots to feed on for the plant, too. But yes, I'd say go for that asap and start feeding. You could run to the store and get molasses (i go for the organic) and the $6 will be money well spent. Go for 1 tablespoon per gallon, moving up to 2 per gallon when you approach week 4-5 of flowering to really carboload your plants. They will be feeding heavily by this point, anyway.
Nice that you're getting the cloning out of the way before the switch. Give them a day or two to recover after cloning before going to 12/12 so that they can recover a bit. That's too much stress to just chop them up and turn the lights off on em. You're getting close tho!
If you achieve the 1 gram per watt goal that can be reached by many genetics out there, you could harvest 2 pounds + , so I wouldn't sound too disappointed with one light right now. Three will be great, and you'll see amazing results if & when you do. But starting small isn't a bad idea right now. It's gonna be a lot easier to maintain your room with one, as 3 puts off A LOT more heat and requires a lot more ducting & a solid vortex fan so that you can cool. Some climates still require a small ac unit on top, depending on the setup & location. You're gonna find your electricity will be MUCH LESS, too. I remember the first time I got a monthly statement for about $500 and could not believe it added up so fast. But if you do things right, it's pennies in the end!
i'm proud of myself cuz when i was going hydro, i didn't understand really how the whole nutes and ppm worked...i just threw some in and it worked. this time i really studied wut the nutes were doing and how to use them...so heres wut i did 
