Suggestions for setup with all new componets and concerns

Looking for an ideal setup with a tablet or Microsoft Pro in the 10-inch range,
My concerns are quick at startup and quick connection of Bluetooth. The tablet will likely be not connected to a keyed source so not an issue it can stay on when the truck is off.
And as little lag as possible. Any suggestions for a tablet and OBD2 sending unit would be great.
Running a 6L LS

I would use an Android head unit. They have low power consumption when ignition off and boot relatively fast. Only issue with them is that most do not support normal Bluetooth as they have custom made Bluetooth stack for hands free operation.

As for OBD2 adapters, we recommend OBDLink:

What Adapter shoud I use? - Connectivity / OBD2 - RealDash Forum