Sounds like you may be over thinking this a bit -- have your read the Intex pool recipe?
http://www.poolforum.com/pf2/showthread.php?17055

With a ~600 gallon pool, I'd plan to drain and refill every 2 weeks, and to use ONLY dichlor and borax. With a volume that small, you cannot run your pool like a pool; you have to run it like a spa. In particular, that means not only using small amounts of dichlor to maintain the pool, but also adding a small amount after each use, to compensate for body goo (sweat, oils, etc) that enter the pool with each swimmer.

I wouldn't bother with the SWCG -- save it for use when you upgrade to a bigger pool.