Climbing Fuji, when to book?

I plan to visit Japan in late July to early Aug next year and I intend to do a tour climb to top of mt Fuji.

I had intended to go last time when staying in Tokyo near mid July but got sick during my visit so I had to postpone it.

How much in advance should you make reservation for a tour that time of the year?

In case of bad weather like thunderstorm, is it common for the climb to be cancelled?

If you become sick during your Japan visit, how big is the possibility to cancel a reservation for a tour? Maybe it depends on the tour company? Or when you cancel?

You are going to hire a tour company to take you during climbing season? Then you can book when you like. I suppose the advantage is they might book space at a hut for sleeping.
Most of the 200,000-plus people that climb/walk up Fuji each year don't use a tour.

Yes my intention was to use a tour. I had gotten the idea it would make things easier like transport, security in case of injuries or sickness, lodging, etc. Also I guess thats another way in not having to hike alone as I would do otherwise. I guess things like renting equipment would be easier too, but not sure..

Unless it is an unnessicary expense to arrange a tour?