I have a pair of Head S8 boots which are a little too high volume for my narrow feet, and of late I've been getting bad arch cramps in them, I imagine because the liner has packed out somewhat and my attempts to keep the boots tight are causing problems. I've just returned from a ski trip where, to my delight, I was able to hire a pair of Head Raptor 115 RS boots, which have a 98mm last (my S8s have a 103mm last, reduced to 100mm by an internal frame - the so-called Full Comfort System). They definitely worked better for me than the S8s, even though they weren't as snug as they perhaps should have been, but I felt my skis responded well to my input, and I didn't get the cramps. I could definitely see myself buying a pair.
They only had the 27 to rent (I couldn't actually see the size mentioned anywhere on the shell, but the liner had 27.0 printed on it), so I couldn't try the smaller size. I did try a Raptor 125 RS in a 26 in a nearby shop, but was unable to squeeze my foot into it without my toes being bent, which backs up my experience having tried a Raptor 90 RS in the same size. So, I have the slightly strange situation where the 27.0 feels a little too loose, but what I understand to be the next size down is too small for me to get my feet into. I did a shell fit of the ones I hired and measured approximately 17-18mm behind the heel.
So, on to the questions:
1. Am I right in thinking that the shell sizes are 1cm apart and it's only different sized liners (?) which make up the half the sizes? If so, it looks like the next size down would give me a shell fit of 7-8mm, which is really pretty severe, is it not?
2. Given the above, would it be a sensible approach to go for the 27-27.5 model, and get an Intuition or ZipFit liner for it? The guy in the rental place said that those boots didn't get many people renting them because they were too narrow and stiff, but it seems it's still likely that the liners would have packed out somewhat.