A 516 Gr 65 is plate material, so I deduct that it has been rounded and longitudinal welded to make pipe out of it.
I agree on the first pass with E 6010 electrode, with the following comment: 30 inches (roughly 760 millimeters) is a large diameter. If the weld is done by just one welder, there's the risk (great risk, by the way) of getting the two pieces of pipe out of line (disalignment) before the weld is complete. I would strongly recommend to make the weld with two welders working at the same time 180° apart one from each other. In this manner, one will work uphill while the other will work downhill. No problem, E 6010 is an "all position" eletrode.
I don't agree with E 7010 for the other passes. Low hydrogen E 7018 would be better. In this case you'll still have two welders working at the same time, but, as E 7018 is an "up hill" electrode, one welder will start at the 180° (the pipe bottom) position welding uphill right to the top; and the other will start at the 270° (the pipe left side) position also welding uphill. When the second welder arrives at the pipe top (0° position), he'll go down to the 180° and will weld up hill until he arrives to the 270° position. Understand?
That's how I used to do with good results back in my days of erector engineer.
As for PWHT requirements, look at the applicable Code. Is it an oil pipeline? In this case, ASME/ANSI B 31.4 applies. Is it a gas pipeline?
Then, ASME/ANSI B 31.8 is the answer. Is it a water main? There must be some AWWA specification applicable.

Giovanni S. Crisi
Sao Paulo - Brazil