You're fine with the 0w30 as long as you don't use it when it's really hot outside. Is recommended to use that during the winter months, but can also be used other times of the year as long as it's not blazing hot outside. I bought some tonight that I'm going to use when it gets a little cooler out. (and it rang up fine... that manager at the Autozone that told me it wouldn't work was misinformed I guess)
Advance Auto is supposed to start the sale tomorrow, so I'm going to stop by there and see if I can buy some more of the 0w30 with the $29.99 sale. The Advance Auto near my house had a ton of filters, unlike the Autozones I visited.
I'll let you know tomorrow what I find out.