I was started on estrogen first, Spiro was introduced at the following consultation. Personally I needed to know my body had a dose of E floating about in it.
Spiro is also a diuretic, why would account for the increase need to pee and the drier skin. So make sure to drink more fluids, preferably water not caffeinated drinks or booze (also strong diuretics!). My doc said Spiro would also help to counter the tendency for the estrogen drugs to retain fluid in the body - so if your on Spiro only you might need to watch you don't become dehydrated? Spiro is also blood pressure medication, so be careful if your BP is normal or low.
The other thing - as I understand it, someone correct me if I'm wrong - the body needs to have some form of sex hormone otherwise osteoporosis could be the end result (often a reason cis women start HRT after menopause). If you're only on an anti-androgen then long term you won't have T and your natural E levels may not be high enough. Anyway, maybe ask about it.