Plonsky seems to have started his jazz career on the West Coast. In 1945, at age 19, he wrote arrangements for Ray Bauduc, the drummer for the Bob Crosby Orchestra who formed a short-lived big band with saxophonist Gil Rodin right after World War II. In 1946, Plonsky recorded four sides with Charles Mingus in Los Angeles.
In a 1948 issue of Billboard, Plonsky turns up playing and arranging for Alvy West, an alto saxophonist and leader of a compact band that featured a trumpet, alto sax, accordion, two guitars, bass and drums. The ensemble included Bob Caudana on accordion and Chuck Wayne on guitar. There also was a vocal group. According to Billboard, "Vocal arrangements for the Larkin Sisters' vocal group are again a radical departure. The gals are blended into the ork intricacies, at times lyricizing and, at times, humming instrumental patterns."
I'm not sure what Plonsky did during...