One who is engaged in Krisna consciousness is already a perfect yoga.
In fact, there is no difference between a Krisna conscious devotee always engaged in
the transcendental loving service of Krisna and a perfect
yoga engaged in meditation on the Supersoul. There is no difference
between a yoga in samaadhi (in a trance meditating on the Visnu form) and a
Krisna conscious person engaged in different activities. The devotee even though engaged
in various activities
while in material existence
remains always situated in Krisna.
A devotee of the Lord, always acting in Krisna consciousness, is automatically liberated.
This is also confirmed in the Fourteenth Chapter of Bhagavad Gita (14.26):
"One who engages in full devotional service, who does not fall down in any circumstance, at once trans-cends the modes of material nature and thus comes to the level of Brahman."
-Excerpt from The Path of Perfection, Chapter 6