If you are after more water flow on 6mm hose reel the answer is to turn up the calibration number rather than the flow rate number. Turn up the flow number makes very little difference but turning up the calibration increases the water volume much more .
I did try that, my controller cal setting was originally on 45 with the 8mm, so i turned it up to 70 for the 6mm and it didn't make any difference? I was once told by a tech at P.F that having the cal setting up to much can burn out the controller, so try not to go above 50 on it?
Changing the calibration does not have a direct effect on water Volume ( Different to flow) EG I can pour 1 litre of water slowly or fast but the amount of water remains 1 litre But i can can choose to pour at different speeds ( Flow)
Increasing the calibration makes the controller less sensitive and means the controller takes longer to dead end the pump when a valve is closed. Calibration needs to change in relation to how hard the pump is running. So the higher the flow rate the more current the pump draws and the higher the cal value will be. Running a pump at 99 flow and 99 calibration means the pump is working very hard and generating a lot of heat. The hotter the pump motor get in some cases may mean this heat may shorten the pumps life.
Water Flow and Water Volume are different based on the initial post. The water volume will be dictated by the ID of the hose so reducing the ID of a hose will mean it can carry less water. As an example if the hose can carry 1 litre in volume a minute as a maximum. Running the pump harder by increasing flow rate will not change this. The only way to get more water volume is to use a larger ID hose which can carry 1.5 litres a minute.
In terms of flow rate a 6mm ID hose carrying 1 LPM could be running at 50 and the 8mm hose carrying 1.5LPM could also be running at 50 .
Hope this helps