Eating seven ajwa in the morning

Q: I would like to act on the hadith on eating 7 'Ajwah dates in the morning for protection against magic and poison. Different qualities of Ajwah are however sold, the best quality being more than twice the price of the lowest quality (which are thin and dry). Would seven dates of any quality give the protection mentioned in the hadith? Or would I have to eat more than 7 of a cheap quality?