I am trying to create a new genesis block. But it is taking too long to compute (still running). How do I reduce ProofOfWork needed ?

Is it this line that I have to modify ?

chainparams.cpp#L117

bnProofOfWorkLimit = ~arith_uint256(0) >> 32;

and change it to some small value (i.e replace 32 by 16)?

also do I have to change nBits ?

chainparams.cpp#L148

genesis.nBits = 0x1d00ffff;