During that time he also played for a variety of New York studio and pit orchestras, including being the concertmaster/solo violinist for the original Broadway production of Rodgers and Hammerstein's Oklahoma!.
In 1953 Pratz returned to Canada to join the faculty of The Royal Conservatory of Music (RCM) and become the concertmaster of the CBC Symphony Orchestra (CBCSO).
Pratz taught at the RCM through 1961 where his notable pupils included Imant Raminsh, Bill Richards, Steven Staryk, and David Zafer.
He remained in his post at the CBCSO through 1961, notably appearing as a soloist in performances of works by Johannes Brahms (1953), Henri Vieuxtemps (1954), John Weinzweig (premiere, 1955), Tchaikovsky (1956), Giovanni Battista Viotti (1957), Ferruccio Busoni (1958), Philip Bliss (1959), Édouard Lalo (1960), William Walton (1962), and Aram Khachaturian (1964).
In 1961 he joined the faculty of the University of Toronto where he founded the Canadian String Quartet (active from 1961 to 1963), and taught violinist Campbell Trowsdale.
During those years he was a frequent soloist with the TSO and actively performed in many Toronto studio orchestras for recordings of film scores, commercial albums, and jingles.
Some of his notable students are Dean Franke, Carol Lynn Fujino, Raymond Gniewek, Myron Moskalyk, Lenny Solomon, and comedian Jack Benny.