Achieving vocal strength is not defined by mere Vocalis dominance in the low range and CT dominance in the upper voice but rather achieving CT dominance in the high range when there is adequate opposition by the Vocalis and vice versa. Indeed CT training is not defined merely by the muscle’s ability to provide longitudinal tension against the contraction of the Vocalis muscle but also by its ability to give in to the Vocalis contraction, and vice versa. The ability to produce dynamic interplay between the two main muscles determine the level of the singer’s physical skill.
When both muscles have been strengthened, their function becomes heightened. The tendency in the lower end would be Vocalis hyperfunction and in the upper end CT hyperfunction. A logical strategy then is to approach the lower end of the voice with light mechanism in mind (i.e. a sensation of lengthening, fold closure and higher overtones) and the high voice with a sense of heavier mechanism. One could easily misunderstand this to mean that one should sing lightly in the lower end and heavily in the top. That would be wrong! The voice is more massive in the lower end and less so in the upper. Yet proper balance in the lower end depends on Vocalis dominance in concert with appropriate CT opposition and conversely for the upper end, CT dominance with appropriate Vocalis activity. When muscles are appropriately trained dominance in the respective registers is automatic. Adequate opposition the dominant contraction by the more passive muscle is what determines balance. If the extremes of the voice are dealt with balance, then the muscular passagio where balance is tenuous becomes more easily achieved since the muscles would have been used to working in concert.
Of course it is not so simple. Beyond dynamic control of the muscles that determine fold mass, fold closure and diaphragmatic pressure must also be properly balanced in order for the fold-mass muscles not to be overly stressed. Indeed, fold mass, fold closure and breath pressure are interconnected, and when ideal muscular balance has been achieved, acoustic adjustments (i.e. resonance) have a refining effect.
Great singing is a complex experience involving dynamic activity of practically all the muscles in the body. In the end, such a balance is achieved by “feel”. Still, the sense of feel is useless if the muscles are not strong enough to respond and produce the desired “sensation”.