Greetings of the day from Siddhivinayak Solutionss!!
As you have asked the query that for Mesha Rashi does north west facing flat is good??
As in the north west you need the check in which pada the door is constructed there are 8 padas in the north starting from 309 degree to 40 degrees.
And the Names for the 8 pada is given below
25 Vayu (Roga), 26 Naga, 27 Mukhya, 28 Bhalata, 29 Soma (Kubera), 30 Sarpa, 31 Aditi and 32 Diti
So out of this 27, 28 and 29 Dwar Padas are advisable the rest will create problems as per the relations, if you have already bought the flat then you can do the remedies accordingly