Hi Payzhayz, that is a good question, and I have not seen a study comparing shorter sessions to longer sessions. However, most meditation teachers would agree that meditation is a number’s game in the sense that the more you practice, the more results you will get.
That is also why we recommend meditation retreats for accelerating the practice and going significantly deeper. Note though that this leveling up in one’s practice also can bring one into a territory that can be challenging. At this stage, the regular guidance of a competent teacher is highly recommended.