flex question.

Hey this is my first time on here so if I don't post this right forgive me. My question has to do with shaft flex to have in my driver. I'll try to be brief so as to get to the point. Couple months ago I went into a store and hit some shots on the launch monitor with a stiff shaft driver. Been playing stiff for years. Well my swing speed I found out was surprisingly about 112 when I was smoothing it. Hence the errant weak drives. If I really went after it it got upwards of 117. So I changed my driver to X stiff and hit 290-300 average with about 112 swing speed. On the course I don't hit it that straight and high at 8.5 degrees but that's more me than any club. Although I like heavier clubs for their accuracy. Recently went in again and hit a xxx long drive krank formula 5 with 5 degrees of loft. It had a midsize grip on it and some decent weight on the shaft and grip. When I didn't really go after it I hit it weak high and fade with about 108 swing speed. But consistently twice I smoked it with using my mike Austin swing principles and hit it 330 and didn't feel like I really went after it that hard. Now I don't remember my swing speed on those I wasn't paying attention to that sadly. My questions are two things. First, do the monitors deceive me an I'm either not at a lower swing speed or I don't actually hit it 330? Would I be stupid to get a xxx stiff shaft because I kill it on the monitor? Thank you in advance for any advice.

Also two things. My drives are more less 270-290 on course. Mainly 280 range. Monitor is 290-300 and errant. But the krank was straighter on errant and the 330 was dead straight. Thanks

If I were you I'd go get a stock X driver (used taylormade or something) and see how it goes after a few rounds and range sessions.

Don't think you can make good judgments from an in-store monitor.

I would try making smaller and more defined equipment changes until you find your stuff. Of course, the more money and resources you have allow you to try a bunch of changes quicker.

I will definitely look into those I appreciate the advice. My current driver is a Nike covert vrs with an oban devotion shaft. The people at the store said it was extra stiff although it is not written what flex it is on the shaft. It just says "05 flex-65 grams." It's a good club but I'm still open to see if it's not the right fit.