Where choosing from many options is unavoidable, you can help people choose (and keep them engaged in the process of choosing) with hierarchy.

Start with a few big options to select from, then gradually increase the granularity of choice until your client is happy to deal with 57 varieties.

That way you’ve educated them in how selection works, and you’ve made them interested in what comes next.

That makes them much more likely to stick with it to the end.