The 50/12 is a lower gain amp that seems to come up on the used market a lot more frequently than most of the Fryette models. The Ultra Lead is the one most known for being fast and dry, but the CLX, CL100, and CL50 are also known for having that character. As per the video I posted earlier in this thread, the GP/DI Pitbull mode was made to sound like the CL50.
If you want the GP/DI to be as immediate and tight as it is capable of sounding then try turning the dynamics control completely counterclockwise, set the power amp mode to tight, run the master volume low, set the gain 1 below noon, engage the more switch, and set it to Pitbull mode. Adjust the EQ and gain 2 to your desired settings.