To bad you dont have the other tuning software. You could flash in a factory LD9 supercharger file, from a cavalier. It would be great for what your running, being a standalone.
Using the P11 PCM? Thats a good idea too...
2008 2WD Ext.Cab Silverado 1500 6.0 V-MAXE38(L76) & T42(4L70E)MAF Only CL Corvette Servo AFE CAI INNOVATIVE LM-2 WBO2