I got a 689 ultralite but when I play with the paint at my fields it's over bored to ****. But I don't want to under bore it either so I'm prob jus gonna get the 684
I have a .688 and find that I should have gone with a .684 most of the time.
Most paint rolls through the .688 these days except for the really old and dimpled stuff.
And to be brutally honest, the CF boomstick is a waste of money unless you get it for really cheap like I did.