Tom. Maybe a cutaway, so she has depth in the fin,for hold ,but less resistance in the base for manuverabilty the fcs 11 fat boy fins in the smaller sizes perhaps
Where is the centre fin lined up relative to the sidebites? Positioning the front edge of the centre fin with the trailing edge of the sidebites feels really good in my 9'0" as a 2+1.
I use a 7 inch FCS II Connect in the 9' and I am 70kgs. maybe a 6" would feel better for your wife?
That's a pretty big fin. I was thinking it would be a good single fin for single fins in the 6'10-8' realm if it was 7"-8". But 9" is big. Maybe a 9' single fin gun? I can't imagine running it in a longboard.
Otherwise, so what Mac said and display it. I've got a bunch of singles I dont use in my kitchen window.
Got me an 8'8". Early days but these fins are gr8 in it. I'm going to go one step further than a set of keels and throw in some S wing 520 twins just to be all out weird.
McCtavish Carver with 60 kg onboard id just got with an FCS connect 6" thruster set up, she won't be overpowering it anyway and with a longer rail line you don't need a lot of fin unless your logging or in some juice or getting up around 80 kg and over.