Kolsch fermentation temperature Hi All,

I'm considering brewing a grapefruit kolsch but I have a bit of an issue with fermentation temperature. The recipes I see state I should ferment at 60F. I already have a pilsner in my lagering fridge, so I don't have anywhere to temp control the kolsch before lagering. My ipas tend to ferment just below 70F but I can prob put it near the window to get it around 64-65F. 

Since I've never made a kolsch before, how big of a flavor impact would I expect on this temp differential?