[GLHS0325]

Welcome to the forum.
Use 10-30w. I use Red Line, Royal Purple or Mobil 1 all synthetic in that order. Amsoil is another very good one.
If those aren't in your budget, lots of higher end conventional dino oils are para synthetic (blend) if you read the labels. Example is high mileage Castrol GTX.

All good choices on the synthetics above.
For conventional I like Pennzoil 5W-30.
I use Mobil 1 5W-30 year round in the GLHS.
The only synthetic I wouldn't use is Castrol.