Actually, I pretty much use any ole 10W-40 the current shop is using. I've been threatened about my '98 Camry (110,000 miles now & no sludge) and my '98 Ford F150 (90,000 miles now and no ticking lifters). Both automaker's dealerships told me that I *had* to use 5W-30 and it was highly recommended I use only the Toyota/Motorcraft oils, etc. etc.
Pffffffffffffft
I think it's about 10X more important that you change the oil every 3,000 miles over what *brand* of oil. 10W-40 or 5W-30.....I think either is just fine.
If I didn't go to the local shop & let them change the engine oil, I'd probably buy Castrol myself and I'd choose either weight above but probably mostly choose 10W-40 just 'cuz So Cal gets so dang hot in the summer. That's my .02!