The only point of 502 oil in a non turbo is to extend the drains out to 10k.
Any dino oil is fine out to 5000 miles in this low output engine, which does not stress the oil at all.
I usually tell people to try Pennzoil or Havoline 10w-40 or 10w-30, even 5w-30 for cold.
If you want extended drains, Rotella 5w-40 is a dual rated gas and diesel oil. It won't help mpg much though.
I like the Mobil High Miles line, esp the thick 10w-30, with the same A3 Euro spec as found in 5w-40 VW 502 oils. There are not a lot of thick 30 weight oils out there to compare....German Syntec 0w-30, BMW Castrol 5w-30, M1 0w-40 is essentially the same. That's what you need for mpg in a synth oil, not 5w-40.
Anyway, just do it, 10w-40 for summer, check consumption. If it's under control, just go ahead and try the same brand 10w-30 for winter.
Believe me, 2 changes of dino oil at 5k gives a better result than one change of synth at 10k, approx the same price. (leave the filter on at 5k).
Here's a toy for you.
Compare the VW specs to the generic ACEA specs, like A3 and A5 that cheap otc synth oils carry. See, w/o the stupid $500k VW 502 spec cert, the price comes down a lot. You also get newer formulas too.