Exactly. If you do decide to go with 11 or even 8 count then I would increase the strands of floss to 4 or even 6 so you get sufficient coverage. What a pretty pattern.
I just looked at the item description and saw that it is a kit. That means that you wouldn't have enough floss if you decide to change fabric count. Convert the Dimensions colors to DMC and you won't have any problems.