I think that this is a very good thing to think about.
One daughter used a tutor. They gave her a practice test to see exactly this – what areas were the ones where she needed the most practice. Then they focused their effort where it would matter the most. It only required a few sessions (perhaps 3 or 4?) and did seem to make her more confident heading into the SAT. We used a very small local company (I think that they have a total of 3 or 4 employees for the entire company).
Of course there are also some very good test optional schools and some that do not consider the SAT/ACT at all.