End effectors with closing mechanisms, and related tools and methods are disclosed. The disclosed end effectors may be particularly beneficial when used for minimally invasive surgery. An example surgical tool comprises a first and second jaw movable between a closed grasped or clamped configuration and an open configuration. The tool further comprises a soft grip mode for grasping the tissue at a first force during which a separation parameter between the jaws is measured, and a therapeutic clamping mode in which the jaws clamp on the body tissue at a force greater than the grasping force. The methods comprise grasping the body tissue between jaw members, measuring the separation parameter between jaws, indicating on a user interface the separation parameter for comparison to a desired separation parameter, and then releasing the body tissue for repositioning or therapeutically clamping the body tissue in response to the separation parameter indication.