Not from personal experience, but...I've heard it's actually recommended to use the 325s.. at least when I told Gregor99 that I bought the Align 315's he said "you should have done the 325's but those will work".
I'm assuming that the Align 315s would be the same thickness as the 325s. I haven't mounted the 315s on my BeltCP v2 yet (since I'm waiting for parts after my first crash), but the thickness difference between the ESky and the Align 315s is approximately 1.19mm (or 1/4" for the ESky and 13/64" on the Aligns) by my calipers. As soon as I get some washers/spacers and my parts from Jag's I'll be back in the air on the Aligns.
First Heli - ESky BeltCP v2 2.4G
The addiction begins!