psgolf; You're getting 250 yard drives with a 90MPH swing speed, and you're complaining? That's about all you can hope for at 90MPH. What you need to do is get on a launch monitor and measure your launch anlge and backspin rate before you decide you have any problems to fix. You also need to take a sleeve of balls with you when you do this to see if maybe a different ball would help to reduce the backspin and allow the ball to roll out more. Try another ball on the course next time out and see if that changes things. You also stated that the ball "doesnt' balloon". That tells me that there's a good chance your ball flight is not too high. With your ball speed, I'd recommend a launch angle of at least 15 degrees.

nh "I am no expert but my experience has taught me that stiffer flex shafts by default have higher flex points or kick points than more responsive or whippier shafts"
This is not always true. Some shafts have the same bend point for all the flexes in that model of shaft. You need to read the spec for any shaft you might be thinking of getting to see if the bend point is different for one flex vs, another.