Which early 20th century Russian experimentalist believed choreographers should study the orchestral scores of their ballets so that their choreography would reflect musical qualities such as instrumental color and dynamics?

The answer is Fyodor Lopukhov.

Explanation:

Fyodor Lopukhov sought for a connection or balance between dancing and music, and held the opinion that, in order for choreographers to be able play their best orchestral music in terms of rhythm, dynamics and instrumentation, they had to be capable of analyzing the scores of their ballets. Lopukhov concentrated on ballets from a musical point of view, than from a dramatic/singing point of view.

a.   it resulted in widespread unemployment.