Voice selection is a creative decision with a technical consequence: the wrong voice makes pronunciation inconsistencies more noticeable and pacing feel off, even when the same text would sound acceptable with another narrator. Audition using a paragraph that contains your hardest material: a personal name list, a few technical terms, and at least one passage with varied punctuation (commas, em dashes, semicolons). The audition is for stress-testing, not for sounding good on easy prose.
During audition, pay attention to three things together: clarity of consonants, handling of short words, and how the voice treats numbers. If your manuscript includes years, measurements, dates, or chapter-style enumerations, listen for whether “2019”, “Chapter 3”, and “Section B” are read in the register you want. If you can’t get a good match, don’t keep searching blindly; adjust the manuscript to reduce ambiguity, then re-audition. For example, rewriting “In 2019 we…” as “In the year 2019 we…” often changes the way a synthetic voice frames the number.