One thing would be to select a lower resolution since the max. 12bit will only allow a sample rate of one per 750ms.
However, that library does not (yet) support dynamic delay depending on the selected resolution, but that should not be too hard to implement.
Adding a variable for the delay and setting that in DS18B20::setResolution() might help. But I’m not sure if too short a delay may cause the “parasitic power” cap to fail charging up enough (for the P variant of the sensor).
I have updated the GitHub repo and published v0.1.14.