I have a pipe API 5L Gr B. (Pipes will be used re-injection pipeline) For root and hot pass Argon TIG 141, and for fill, cap pass basic MMA 111.

I have chosen ER 70s-6 and E7018-1 H4. But I am not quite sure if this is correct. & How can I calculate thickness of passes?

Thanks for help!

Best Regards.