I personally think 10k is a long interval for a little engine, but driving conditions are a factor in that, I'd do more 6-8k or every 6 months, which is what I typically do anyway, oil usually contaminates faster than it wears out unless your always freeway driving.
With oil weight, I spoke to a top oil technician once, the only real reason to use thicker oil, if if yours is burning enough to justify it, but good engines don't burn oil, so stick with factory fill recommendations.
There is a good oil guide in the cars handbook, from memory it lists anything from 5-15/whatever, depending on your average temps where you live, in Qld you easily get away with a 15/XX cause it's never really cold here, though if your after maximizing your economy the thinner oil help that, some engines also have a sweet spot for some weights, where they run the smoothest.