Two decks, one 80% full sun one 90% shade

I'm looking for opinions on what product to use in my situation, or maybe I need two different products.

New house in SC, just south of Charlotte NC. Pressure treated pine, 2 to 3 months old now.

On the back of my house there is a 8' x 22' covered balcony so it only gets a little sun on one corner in the morning. The front of the house is near full sun from about 9 AM on, that is where our front steps, landing and a smaller 6' x 8' balcony are.

Both front and back are PT pine deck and steps, painted rails and covers. Basically the horizontal traffic areas are not painted and everything else is.

I've been researching everywhere and have determined that there are many opinions on the matter, hard to know what to do.

I think oil based is probably the right choice, but have read that in full shade it will mold or mildew. I've been looking at TWP, Defy, Armstrong and Cabot. I figure as long as it's generally agreed to being one of the higher recommended products I'm good. There are so many opinions it's unbelievable.

Also, (mixed opinions here too) for a new deck should I use a brightener then lightly sand with 80 grit?

Thanks,
James