For a mid-flex board like the SL, the 153 or 155 will be suitable. The 2cm difference won't be noticeable unless you happen to get a chance to demo them side by side.
Say you do get the chance, here's what you might notice:
The 153 will be easier to flex
The 155 will ride a bit more damp
The 153 will give you a little more control in terms of edge to edge and spinning
The 155 will ride a bit faster
At your weight, a 153 down from 155 isn't drastic. Now say me, being 180lbs, has been riding a 158. I could go down to 155 just fine with minimal differences. However, if I go down all the way to the 152, the differences will be easily discernible.
Given your foot size, the 153 sounds to be your best bet.