Absolute vs soft dry fasting

Hello,
I was wondering does anybody know how much more potent an absolute fast is compared to a soft dry fast. I've completed several of the latter, never going beyond 3-4 days but I've always showered and brushed my teeth. There are times I've even found myself prolonging the showers unintentionally, for up to twenty minutes at a time. Does completely eliminating all contact with water bolster autophagy and if so, to what degree?
I've also read that fasting in general has limited effect on thyroid function which is primarily the reason for my doing it in the first place. Is that true?
Any information would be greatly appreciated.
Thanks in advance
Random88 Tweet