You can cut the Piggyback connector off of the 30-0334 harness and wire it in, directly behind the OBD2 connector. Or, you can get a 30-0300, which has individual wires for the CAN lines. And, have it re-FLASHed to OBD2 mode.
Attachment 98954
The CANH and CANL wires, from the 30-03xx connect to PIN6 - ISO15765-4 (CAN Bus High ) and PIN14 ISO15765-4 (CAN Bus Low ) pins of the OBD2 test port connector.
Avoid the temptation to power the gauge from PIN16 ( +12v ). It is, as shown, always on. And, the gauge will drain the battery, when the engine is not running.