Plan. B if I can't get Amsoil Z-Rod?

[Erik]

My car will be going in for some servicing the first of next week, and I don't think I'll be get Z-Rod by then.

I was looking for the High Mileage Mobil 1 at the local Wal-Mart, and all they had was 0-20 and 5-30.

Being in Canada, some of the smaller brands that can be bought in the US aren't easily available up here.

Any plan B recommendations? Oils that would do lesser harm?

Or am I overthinking it and any quality synthetic of appropriate weight would work ok for the time being.