Originally Posted by Duce-hands
The chord progression is Bb7|Eb7|Bb7|Bb7|Eb7|Eb7|Bb7|Gmin7|Cmin7|F7|Bb7|F7
Usually the measure, where in your progression indicates "Gmin7", there would be a ii-V of the following measure (Cm7). Or, some variation, such as iių7-V7(-9) or Dm7b5-G7(b9) resolving to Cmin7 (which immediately becomes the iim7 of Bb). The tune "Bloomdido" (in Bb), uses C#m7-F#7 (ms. 8) followed by Cm7 (ms. 9).
The term "turn around" usually occurs at the end of the progression. In a 12-bar blues, measures 11 and 12 could utilize the above mentioned "I - vi - ii - V". This "turns around" to the first chord of the progression, and you start all over. There are many options for turn arounds.
In a 12-bar blues progression, the EIGHTH measure can have many substitution possibilities - check the literature.