I think atleast 35% vote will be required for a majority.

With 40% votes a party will probably get around 50 PR seats. The party will require 88 seats in FTFP, which is about 53% of 165 which is very likely. Anything above 30%, if coordination is good can get a majority or a super-majority in FTFP (See latest UK election). So, 40% vote-share for a party will almost surely give single-majority to said party in our system.

With 35% it is trickier. That would translate into about 45 PR seats. 93 FTFP seats would be required for majority which is about 56% of total available seats. This is achievable. In fact, very likely if the party can coordinate well.

Anything below 35% will be tricky. Much more FTFP seats would be required to compensate for PR seats and although 30% maybe enough to get majority or even super-majority in FTFP seats, that would require good coordination.

I think atleast 35% vote-share and good ground network will be enough to get a majority in our system.