I'm trying to add a tach to my 2000 Arctic Cat. It has a 370 2 stroke 2 cylinder. It requires a 4 pulse tach (which is extremely expensive). I have a 6 pulse and need to convert it with a universal pulse adaptor. What in : out ratio would I need to use? I'm not super familiar with pulses or tachs in general (I know the basics but that's it) so I'm not too great at deciphering this sheet.