Anyone have a good link to an oil viscosity graph so I can compare

SAE 30 oil to

10W-30, 10W-40, and most importantly to 15W-40

5W-40 would also be nice too.

I need to put some oil in a Kubota diesel engine and its first recommendation is SAE 30 with or 10W-30 or 10W-40 as options for above 25C ambient.