Agreed. Hit all the drivers you can and play the one that works best for you in terms of feel and playablility. You will probably find the more forgiving drivers will work better for you (obviously), and that you will play yourself out of both your set and driver as you improve. Now, this may take a long time, so don't read much into that.
If the Great Big Bertha II is the driver you are set on, buy a Great Big Bertha Titanium. It has a bigger sweet spot and lower center of gravity which will get your ball airborne easier. Also, try it out before purchasing. Callaway shafts are notorious for playing softer than they actually are. I swapped mine out for a Grafalloy Blue Stiff, which actually plays a bit stiffer than the norm, but that's built for my swing.
I think if you are just beginning, stay with a regular flex until you obtain good control. Then you can start to increase your swing speed and may warrant a stiffer shaft in the future.
As for changing equipment during lessons, i wouldn't shy away from this. Your instructor should be teaching you "the golf swing", not "how to use your equipment". If he is, he's going about it the wrong way, which i would say wouldn't be the case. If you feel as tho a change is needed, by all means go for it. Being positive and having a good mind set with optimism is a huge battle with golf, especially when you are learning.
I had a friend that i gave some "pointers" to when he was starting out. His driver was giving him fits and he asked me to hit it. Well, it felt like i was hitting the ball with the bumper of his car, no feel and zero feedback from the shaft. Terrible. He opted to go with a new driver and found a new sense of well being when it came to the game. He now wanted to practice and did so when he wasn't much in the mood for it. That single peice of equipment took serious strokes off his game, not so much because of the added distance and accuracy, but for the positive outlook he now had for the game.
My GBBII is somewhat tailored for my game. It's 1.5" over "standard" length and the shaft has been splined. It's the Pro Series, which is less offset and has a higher center of gravity versus the regular Great Big Bertha.
If you have any questions Nam, let me know. I've hit pretty much every club Callaway has out there and i can give you my two cents worth on each.....except the new ERC Fusion fairway woods, i haven't hit those.....yet.
R35