Head Faith & Heart Faith?

Regarding the sincere intentions of many Reformation leaders to balance head and heart faith, semantics aside, I believe the core issue here is the doctrine of justification by faith (alone). To splinter the tree by attempting to consider heart faith as opposed to head faith is like extolling the virtues of the bottom piece of bread in a Big Mac as discrete and completely unlike the top piece of bread. These two pieces are in fact one sesame seed bun, period. Faith alone - "Sola Fide," with our hearts and minds united in a single perfect sphere. There is a point of diminishing returns in the human tendency to over-analyze, super circumscribe, and subdivide any idea, even going "beyond Scripture." "He who believes in the Son has eternal life; but he who does not OBEY the Son will not see life, but the wrath of God abides on him" (John 3.36). "Obeying the Son is parallel to believing the Son. True faith involves moral commitment to Jesus, and persistent disobedience to Him signifies a lack of real belief" (Spirit of the Reformation Study Bible p. 1706). And so we can conclude that the mind (head) is instrumental in the act of obedience because we must first "know" what we must obey. It would follow that a moral commitment to Jesus requires a selfless engagement of the heart and that both agents are required to facilitate what we would consider to be saving faith. I am so glad that through synergism of head and heart we can be justified by one faith and therefore have peace with God. One God, one faith, one baptism. Sola, sola, sola. Please excuse my Latin. Lol!