for a good cheap priced oil,Cenex Maxtron is worth a look,,forumulated by themselves (CHS) is the parent company, really a sleeper oil ,only found at Cenex gas stations and distributors.
or use a good stud finder and use a construction screw to mount your stuff on. as mentioned, or a 3/16 toggle bolt will work too, nutting it so the head and part if the screw sticks out and a washer against the wall.
seems like the Pennzoil 5w-30 ultra acts like a 0w-30 in the mrv and ccs testing compared to some 0w-30 other oils, perhaps due to the GTL base fluid used and other additives.
Pennzoil Ultra Platinum 0w-20 would be a good choice and even after break in the 5w-30 would be fine over summer months, very fine oil and is available at WM or other places, Fram ultra filters or oem.you may want to check ccs and mrv viscosity's also if comparing to other oils. pour points dont...
if you are a Mobil 1 fan boy,look at the 0w-30 AFE,as its a reasonably good oil. Though Pennzoil ultra Platinum is a very fine oil too worth considering first..