I have size 47.5 nepal evo boots and find that many crampons even when set up correctly don't seem to have as much front point sticking out as when set up with smaller boots. This problem is increased once the front points have been sharpened a few times.
I currently use grivel G14s and am considering the grivel rambo evo4 has anyone any other recommendations.
Check the manufacturer's information. They are said to fit most makes / sizes of boots. There are adjustable size fitting for the front points ranging from about 2cm to 4cm. And you can go dual or monopoint as you wish.
Quite a lot of crampon manufacturers have either one or two types of extending or shortening options to fit the entirety of humanity's variations. Retailers, online or street, who can be bothered dealing with these variations are thinner on the ground.
I have some Petzl Lynx crampons. I'm a size 12 boot so I bought an extension bar for the Lynx which you can get from plenty of Petzl stockists. Easy to fit and sorted the problem... Anyone want to buy the old one... ;-)
In reply to rob1:
As someone already mentioned but to make this foolproof, use long extender and they fit up to size 50. I have Nepal Evo size 47s and I use G12 this way and there is no problem whatsoever.
In reply to rob1: My spare crampons which are CAMP ones have still have 3 or 4 holes of adjustment left when fitted to my Aku size 47.5 boots. Main crampons (cassin) are on last hole and just fit. Think this is less of a problem than it used to be. I remember fighting crampons onto boots up until 10 years ago...