Sober’s “The Design Argument” is currently freely available at the Philosophy of Religion section of the Cambridge Elements collection, as provided in a previous PS thread:
Elements in the Philosophy of Religion
Sober provides a careful analysis of the Fine Tuning Argument. He does raise the objection that there is no principled way to choose a probability distribution for the constants to assess their likelihood under various hypotheses, but he finds this argument unconvincing. As a counter, he provides what he thinks is a principled way to provide a distribution as the limit of a family of distributions.
However, Sober does think the Observer Selection Effect argument against the FTA invalidates the cosmological FTA by the Weak Anthropic Principle: “what we can expect to observe must be restricted by the conditions necessary for our presence as observers”. Once the WAP is taking into account, arguments for the FTA fail, according to Sober.
Some raise the firing squad counter to the WAP, but Sober shows why it does not apply to the cosmological FTA, at least in his view.
See also here for details on the nature of the firing squad objection to the WAP and for another look at the FTA overall,
https://plato.stanford.edu/entries/fine-tuning/#AnthObje