I know people who have done exactly this. You’re looking for grad students - they often know exactly the right amount, and are very willing to work for some ext

I know people who have done exactly this. You’re looking for grad students - they often know exactly the right amount, and are very willing to work for some extra cash, and some (not all, but some) are happy to teach. One way to find them is to contact your nearest research university’s department of math/physics/whatever and they can help match you with someone, or just post a flyer in their department office.