I am a bit confused about doing the meta analysis with my data. Given z-scores I calculate p values in a way: p.values = 2*pnorm(-abs(z)). Then I would like to apply Fischer/or Stouffer methods to do the meta analysis. Those methods work with one-sided p-values, so I just need to divide my p.values by 2 (p.values/2) and perform combine.test(p.values/2) in R?

In this paper I found following: After combining the P-values, if desired the resulting combined P can be again converted to a two-tailed test by multiplying it by two.

So, after I get the combined p values, i multiply them by two to get back to the two-tailed test.

Would it be a correct procedure?

I found this post but I do not understand what is $$ {p}_i $$ in this case. Is it two sided p-value or one sided?