Here it is impossible to answer unequivocally, because everything depends on the tobacco, the strength, its quantity (you can tamp 30g, 50g), the method of scoring (in touch and without).
Everything affects.
You can smoke for an hour, but in the end it will be carbon monoxide.
The standard, convenient, optimal smoking time for any bowl is about 40 minutes.
On Alien-mini, since the clogging is less and smoking is more intense - 30 minutes.
We can say that Alien is a mini-bowl egoist. It is more suitable for one person and for juicy solo smoking. It is also suitable for several people, but the time will be less.