When I reduced the oestrogel (I got down to 1 pump) I still took the same utrogestan dose (2 x 100mg for 14 days if I remember rightly - sequi regime). As bombsh3ll alludes to, I think my problem getting on with HRT was that my own hormones have been widly fluctuating for years, so I could never get the balance right and I think I had too high oestrogen a lot of the time.
When I was on Evorel Conti patches (containing both oestrogen & progesterone - conti regime) I cut them in half.
So, in both cases, I think I was getting sufficient progesterone to cover the oestrogen.
Hope this helps.