Answer
(Fatwa: 1470/1225=L/1429)
(1) There is no limit.
(2) It is mentioned in Hadith, used to apply so much oil that his head cloth used to be like the cloth of oilman. (Jam?ul Wasaail 1:103)
(3) One is allowed to comb hair daily if needed, but it is undesirable to pay so much attention to it:
واما حدیث النھی عن الترجل الا غباً فالمراد بہ ترک المبالغۃ فی الترفہ المشعر بانھا من ھوی النفس والمشیر بانھا فی تنظیف الباطن اولی (جمع الوسائل 1:99)
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband