No, 7 nights is fine - I had 6 nights in October and could have stayed longer. I don't think it is worth splitting the trip because of the hassle of moving. Plus, Vilamoura is a pleasant short drive away so you can easily visit if you like.
It is worth considering which location suits you best and what the cost difference is - the Conrad can hit some pricey room rates in high season.

I'm looking at booking another trip later this year but might end up returning to the hilton since it is around EUR100 per night cheaper. Both hotels are good - the Conrad is definitely best, but the value at a 100E delta is debatable.

Enjoy your trip, wherever you stay!