I am a fan of Penrite products.

The Penrite guide recommends HRP 5 (5W-40) for your car followed by HRP 10 (10W-50) and 10 Tenths 0W-40.

I use the 10 Tenths Racing 10W-40 on my last oil change and have a few bottles of the 10 Tenths 0W-50 (now renamed 0-W40 as they removed the "extra 10" marketing from it) in the garage that I'll use next time.

The best way to get an accurate reading if the oil you are using is good for your car you need a oil pressure gauge and measure the oil pressure at operating temperature, it should be something like 10-15psi at idle (don't quote me on that, you will have to find it in a manual to be sure).

That's something I've been meaning to do for a while now but haven't gotten around to, I was thinking about mounting a oil filled oil pressure gauge under the hood but haven't looked into it any more than just thinking about it.

If you have a prefered brand I'd stick with it over the course of a few oil changes and vary the viscosity depending on your oil pressure readings until you find one you are happy with.

Synthetic or semi synthetic is prefered but if you have a old car that has been running on mineral oil all of its life.