coolant temp vs oil temp, oil mixing

[spdracer at mail.utexas.edu]

I'm curious as to the oil temps you see while cruising on the highway and in
stop-in-go traffic.  I've seen my coolant temps on the highway be 170-200F in
50-100F degree weather.  I can tell the oil is getting toasty in the hotter
weather as the oil pressure gets lower.  In traffic, the coolant goes up to
212F when the fans kick in.  I'd imagine the oil temps are around 210 during
those conditions.  With the hotter weather now, the oil pressure is getting a
bit low for my preference and I was thinking of mixing some mobil 1 5w-30 with
15w-50.  Will this actually form a solution thats somewhere in between the
weights or would it just be a mixture with parts 5w-30 and 15w-50.  My
intutition tells me it should form a solution with properties in between, but
i've never read/seen any info covering this.  they're both oils so they should
form a solution.... i think!

Khiem