I’ve found this leverage point to be a big deal. Straight pipes that I thought weighed relatively light but were over 6 inches long I’ve had more trouble clenching than noticeably heavier pipes just over 5 inches.2 oz or less is kind of the magic number for me. The length makes a big difference, the longer the pipe, the heavier it will feel. Think lever. The shaping of the stem is significant. Wide and thin with a decent button make it easier to clinch.
For straight pipes, I find the ideal maximum combo (where you can find it) to be around 35 - 38g (1.23 - 1.34 ounces) and ~5.5 - 5.75 inches.
It can also matter where the weight is—a heavier bowl and lighter stem will pull downward more when clenched than a more balanced pipe of the same weight.