Answer
(Fatwa: 1934/1800=D/1429)
The main fardh in ghusl is to pour water over the whole body in a way that no part the body is left dried. It is Sunnah to pour water thrice on whole body, and it is undesirable to waste excessive water unnecessarily. You should do what is fardh and sunnah and shun from makrooh. It is good if you have a bath with bucket, you may use more water also. Using shower is lawful if unnecessarily excessive water is not used; otherwise have a bath with a bucket with water. It is not fardh or wajib to use one bucket; the buckets are of different sizes.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband