Youre over thinking the ST a bit, its a bike designed to get get on and go and enjoy the rode. The trouble with gaugesis, that they take your attention away f4rom the road while you try to read and interpret the result, The lights tell you that a problem existd, and you had better attend to it. Sts go forever, I have never heard of one that had an oil pressure related problem, and some have been going for many 100thousands of Ks.
I doubt that anyone can give you more detail on the pressures, as the only thing to go on is the info available in the maintenance manual