Quantum is fine, and I concur with the statements made above. I would say that the age and condition should be evaluated by a sailmaker at your expense. Those sound like bullet-proof, all weathers sails, the sort I would pick. But if you envision mostly light air sailing, you either have the wrong sails, or the wrong boat. What you have is an oceanic passagemaker with passagemaker sails. Now, if you can stand doing 4 knots all the way south, there's no problem, and you and the boat can certainly do 7 when the wind pipes up to the point that a lesser, more lightly canvassed boat would be over-pressed. But if you want to make 6 knots in 9 knots of wind, get a J boat.
The Valiant 42 is proven, comfortable in a seaway, and when properly handled, is an excellent choice for a liveaboard. But she's not fast and she's not particularly modern or built like a Beneteau or a bigger Hunter below. The sails aren't really at issue.