Sonic checkers

I build generator turbine combustion parts so I have acess to too many things. I think the tip will work fine but I did findout something interesrting. The readings from inside to outside vary...I forgot the exact number but it was around .030 I'll check tonight. Also there was a difference from flat to the pipe and again I'll double check that all tonight. Will a cylinder wall I think the tester will work just fine. I do have a 80's 360 block that I left in IL with my parents that I'll get back over here right after christmas and start cutting on.