I don't think you'll want to mix Super Saver and Simply Soft unless very soft areas coupled with fairly hard areas is the effect you're going after. They're also not really the same size (at least not always, some Super Savers are pretty thin, for that matter not all Super Savers in the same color are the same size).
8's are what I usually use for Simply Soft. I don't think I've knitted Super Saver, I use that for crochet.
Since you say you can't manage to turn and do the second row your stitches probably aren't too tight. That's the cast on edge. I don't know what cast on you're using but cast on around both needles (since you only have one size), that will loosen up your cast on edge, it is common to cast onto larger needles than you're going to be knitting with. But it will still be tight, things loosen up a couple rows in.
As far as turning, you just flip the piece over and start knitting the other way. That loose stitch you get at the end of the row goes away with practice. The odds of picking up knitting and being an instant expert are slim, it takes practice.