And one rule more: Drink always a beer in the hut.
So finally I have to find out, that I am not an alpinist
I prefer red wine
I soloed Gran Paradiso and Lagginhorn. There are some other alpine 4000m mountains I did in double team (together with only one mate) but unroped all the way leaving the rope in the backpack (Allalin in April, Alphubel and Strahlhorn in May, MB du Tacul in June) or we only used the rope at some certain passages where crevasses might be under the snow (Weißmies nnw, Breithorn traverse, Bishorn).
There is no general rule for safety at any alpine 4000m mountain. It depends on personal fitness, skills and the conditions and those can vary a lot. Anybody who says: "soloing this mountain is no problem or that mountain is dangerous" can just refer to certain conditions and personal skills. Gran Paradiso for example was a safe solo climb for me in early summer after a winter with much snow. Lagginhorn was safe by means of objective danger, but there was blank ice in the summit ice field and crampons and some skills and good nerves were needed. Someone who doesn't stay cool might have been in problems.
Don't underestimate Mont Blanc! The Rother guidebook says: someone should have done at least ten 4000m mountains in the Alps before trying Mont Blanc.
@sjarelkwint: if you are honestly thinking about taking your sleeping bag inside your backpack up any PD-route on an Alpine 4000m peak you should get some skills on lower mountains first and learn about mountains and yourself or pick a partner that might teach you. This forum can't replace a solid learning process from gaining practical experience.