I ' m actually 5 ' 9 and 22 . Haha . Nonsilly pose feat . doggo Fits <| sep |> I should remember this one . I constantly talk about what I will do and how I will do it but I take few and rare steps to get there . I acknowledge this but I still haven ' t fixed it . <| sep |> That ' s multiboxing isn ' t it ? <| sep |> Awesome mate ! I will have to get looking in to that , thanks <| sep |> A new type of spaghetti has been cooked . <| sep |> I ' m not sure but continuing studies is not what you are looking for . It ' s for people who have degrees who are trying to get a certificate . <| sep |> No , thank you . <| sep |> I assume you are talking about an optical flat and just need flatness , Ra , and profile ? Ive never used an interferometer but sue to the 300 mm size , it depends how much surface you want to cover . Usually for surface finish , if the surface looks uniform , 13 traces should be good . Since the size is fairly large you might want to take a few more traces . Assuming you do 10 traces and are familiar with running the machine and the settings needed it should only take 3045 minutes don ' t forget calibrating your stylus tip . If you are only measuring flatness with the CMM over 300 mm diameter , then you probably want 2 dozen or more points . Its a fairly easy measurement and should take an experienced user 510 minutes with probe calibration . I am only assuming that is all you need to measure . Like the previous commenter said , if you give us a print it would be much easier to give you an estimate .