39T or 40T sprocket for 1098?

[GeenaG]

I need to change my chain/sprocket on my 2007 1098. I find the current gearing 15/38 a bit too tall for my liking. I will be doing a couple of track days at Calabogie, maybe Shannonville. I will also ride it on the road. Is a 1 tooth increment noticeable or should I go up 2 teeth? I would prefer to keep a 15T countershaft arrangement. Any thoughts?