Re: How to select a coach
You're talking about live games?
Are you currently profitable at 2/5?
I would not put any weight at all into one single MTT finish, it is not a meaningful piece of data. If he has a historically profitable sample size in MTTs (not an easy thing to find since so few sites take into account buyins when they show MTT winnings), then you at least know he can help in MTTs.
But cash games are a bit different, even live FR.
I would find out who he has coached before. At $75-100, that's below what most good 5-10 coaches are going to charge, but it could be a complete waste of money if the person hasn't taught before.
Ideally you want an active winning player that can at least convey what makes them successful to you. Better is a fact-based coach, someone that can tell you why certain strategies work, rather than just having you copy what happens to work for now.