Some golfers are... strange.
They don't keep things exactly the same. A miss-mash of wedges, with different lengths and shafts. I'm just as guilty: I tend to not stick with the same ball.
But one area where I don't think it's a good idea? The grips. Especially when you use oversized grips on only the driver. Why?
You shouldn't be using oversized grips on the driver only
The grips are the only connection to the club you have! Why mess with that, make things different?
If you have an oversized grip on a driver, you should have them on all the other clubs, as well.
Some people tend to think that they hook or slice with the driver because the grip is too small. They then go with a different-sized grip for everything else because they feel they hit them well.
But they don't stop to consider other factors in the driver.
I mean, if it's too long for you, you'll struggle to control the club face. Same with a swing weight that's too light; if you can't feel the head throughout the swing, you risk coming over-the-top, creating a slice. If your swing weight's too high, you risk creating hooks.
None of those things have anything to do with the grip size. It's like putting a band-aid on to fix a broken bone.
Can a grip affect your shots?
Yes. But the catch is, there's no universal "do this to fix that" fix for grip size.
It's mostly about comfort.
When you feel you have to put a death grip on the club, you risk slices, but hooks, as well. Too much tension in the hands and arms can prevent you from closing the face through impact like you're supposed to (a slice). But it can also lead to overcompensation (a hook).
There's no right or wrong answer. Get the grip- the size and material- that is comfortable for you. How much larger do you go, though?
First, start off by knowing that, unless you request something larger, the grip size will be .900" in diameter. That's the "standard" measurement.
Then, look at your gloved hand and its longest finger. Just how long are they?
Let's say your hand length is 7.75" and your longest finger is 3.5". That, based on the Wishon Method, would require a grip that's +1/32", or .930". Don't just do that for your driver, though- do it for all your clubs.
It just makes no sense to do an oversize grip on just one club. It's all about consistency.
What about "Jumbo" grips?
There are some people that prefer the extra-extra-large grips. That's not crazy.
Just like everything else in golf, there are some golfers that defy what the measurements would dictate they should use. There aren't a whole bunch of them, but enough that some people should be OK with saying "could I try that?".
The good news about grips is, they're (relatively) inexpensive. At least compared to the other components.
If your fitting says to play grips with two extra wraps, but you want to try a super-big grip, go for it.
This would be the only time where I say "do it on only one club". Personally, I'd try it on the 6-iron, but you gotta do you. I like doing it with the 6-iron because it forces you to make a decision after your test... but that's just me.
If it works, great! Just make sure to go back and regrip all the other clubs in your set. If it doesn't work, you're out $20 or less (depending on what grip you tried).