[dragonwriter]

Two experiments getting a large variance in p-value for the same hypothesis says that (a least) one is either done wrong or an extreme statistical outlier in the space of potential tests of the hypothesis, but it doesn't tell you which is wrong. And the effect of sample size is already reflected in p-value, it doesn't tell you which of two studies with apparently inconsistent p-values is more likely to be the error or extreme outlier. To do that you either need specific evidence of error or more studies which provide at least probabilistic evidence of which study is an outlier.