Re: Oils other than Mobil1?
"garage 100+ deg.." April-May is odd here, hot earlier, chilly now. That is why both ends of my "working" garage open and have lotsa fans. That said haven't seen over 93-95 OAT for a few years now. Of course by mid-June humidity is the same.
The 100 days of summer is when utility bills go up and you do not go outside unless you must.
That is why 5W-40 or even 10W-30 is fine here.