It seems as though the two types of work outs are contradictory in a sense that one is designed for extreme cardio conditioning, and the other for pure strength. That being said, which is the proper balance of cross fit and strength training. This question is more inclined to the experienced weight lifters and strength coaches.
I’m not sure if there is a “proper” balance between the two, but the first question I would ask you is what is your ultimate goal?
Seems like CrossFit incorporates many facets of fitness–including strength–but also power, endurance, agility, etc… It would also depend on how many days a week you are currently weight training.