Tach settings

[dfunde01]

I just upgraded the 2 cycle outboard on my pontoon from a 50 HP Yamaha to a 90. the tach pegged over 7000 when I took it out for its first run. Pulled the dash panel and found the tach option set at 6C 3P. There were various other setting for 4 and 8 cyl and pulse rates. there were also two settings for 5P and 6P with no reference to number of cyl. the 90 Yamaha is a 3 cyl as was the 50 it replaced. Set it at 6P and it appears close to correct. What is the correct setting?

Thanks,

Dave