xsimplicity

Hi everyone,
I just recently purchased the Burton Deja Vu flying v 2013 and the Burton Bootique 2013. I was just looking for a compatible or recommended binding to go with my board and boots.
I currently have the Burton Scribe Est 2013 binding but i found that the ankle strap is too big and gets caught with the knob on the boots. I was considering a Burton Lexa Est 2013 or even the older model 2012. I know that this is a more stiff binding so wasn't too sure if it would go well.. I don't really understand the stiffness scale (is 5 considered really stiff? because for boards, some people say that a 3/10 is stiff..) I'm a beginner/intermediate rider (not going to parks and stuff, but regular freestyle riding on the slopes). Any help would be greatly appreciated. Thanks!