So the right answer is that salvation is 100% divine and 100% human – the divine grace being prior to human faith and works. That’s the Catholic position and I would challenge you to read the New Testament with this Catholic paradigm in mind. I think that you will find that it sheds light on passages, brings about a cohesive whole, and clarifies those “difficult passages” that Protestants avoid or dismiss (e.g. James 2, Hebrews 6).
Works (including involvement in baptism and other sacraments) are 100% absent in the paradigm case of Abraham (Genesis 15:6) and 100% absent in the historical descriptions of how others were justified (Mark 2:5, Luke 7:50, Acts 10:44-48, Galatians 3:2-9, etc.). Works were present in Abraham's life, a point made in James 2, and they would have followed faith in cases like those in Mark 2, Luke 7, etc. But justification occurs at the time of faith, not at the time of baptism or any other work. Not only would it be a less natural interpretation to dismiss these passages as exceptions to a rule, but some of these passages are presented in contexts that are about what's normative, not what's exceptional. People like Abraham, the tax collector of Luke 18, Cornelius, and the Galatians are treated as if the means by which they received justification was normative. Every one of them received justification through faith alone, without the presence of baptism or any other work.
Paul often points back to how people were initially justified (Galatians 3:2, Ephesians 1:13-14, etc.). The Judaizers couldn't argue that while justification is initially attained through faith alone, works could be added as means of maintaining or increasing justification later. It seems that Paul viewed the initial means of attaining justification as evidence that works couldn't be added to the process, as a means of justification, afterward.
But let's set that point aside for the moment. Assume, for the sake of argument, that works might become a means of maintaining or increasing justification after justification is received. The fact would remain that scripture contradicts Roman Catholic soteriology on the issue of how justification is initially attained. Passages like Genesis 15 and Acts 10 don't reflect a Catholic view. They reflect an Evangelical view.
Yes, Catholicism teaches that "the divine grace [is] prior to human faith and works", as Taylor Marshall puts it. But scripture teaches that justification occurs, normatively, prior to baptism and other works, which is inconsistent with Catholic teaching. To use Marshall's examples, scripture does suggest that Jesus is both God and man and that Peter was both empowered by God to walk on water and walked by his own power. Thus, we have to account for both. But when baptism and other works are absent from passages of scripture like the ones discussed above, there are no works to account for. You don't need an explanation that includes both faith and works. To the contrary, an explanation that includes works is wrong. It includes too much. It's more reasonable to read passages like Hebrews 6 and James 2 as Evangelicals do than it is to include works in passages like the ones I've discussed above or to dismiss those passages as exceptions to a rule.