I had the fortune of picking up a Jerry Franklin Southwest, new, back in 1992 and it is 22 oz.... yes 22! I had never shot with anything over 19.5 at the time, but the cue is so well balanced that I quickly got used to it. Besides the 5 year break I took from the game, I shot with that cue exclusively for the better part of 7+ years from '92 to '04 until recently when I decided to just put the cue away for now.
I picked up a Capone at 18.9 oz and it has been a little transition, but again this cue is very well balanced and the learning curve was quick. I also, just 2 weeks ago, got a Skip Weston at 19.5 oz that has an ebony forearm, so the cue is a touch forward weighted compared to the Capone, so the difference in the 2 cues feels a little more than the .6 oz. But the Skip hits super strong also and plays terrific.
I guess what I'm saying is that as long as the cue is well balanced, the weight of the cue can be overcome, but if the weight is poorly distributed, I don't care if it is at "your" perfect weight - the cue will not hit well.