depends on from where u start. These guys started at Testa Grigia on the Swiss-Italian Border (3400m), then they followed the slopes up to Klein Matterhorn (3820m) and then went for the peak. When I got up there 2 years ago, I did the pussy route and started at Klein Matterhorn (which is only around 350m below the peak) and it took me about 2hrs to get on top. As it's the easiest 4000er in the alps you can do it without a guide, if only you only good weather, good equipment and no fear of height
