Just as you had to try a few different settings getting the Modbus value to show up in groov View, you are going to have to try a few different settings in Node-RED.
Modbus is a very poorly implemented ‘standard’, so trial and error is the best way to get it working.
You have not mentioned what device you are using, or provided a link to its Modbus command manual, so you will need to test things out making notes along the way so you ensure you test all possible combinations.
This is a great Modbus troubleshooting thread here, you will also find lots of Modbus tips in by using the search in the forums…