What is the pump model should be a CPT2 = Rated at 300 USG GPM Waterous underate its pumps considerably.
Also consider if you want to know MAX LPM t low pressue or MAX LPM at high pressure.
If you go to Waterous web site, download a chart, you will see the performance, when RPM and HP are considered.
You will require the Deutz RPM and HP output info to match the pump to the motor. Deutz will have 3 out put measures - all to Din standards - pick output with the highest HP for the intermittant output requirement - Pick the lowest HP output for a 8 Hr pump run (flood pumping)
Hope this helps.
Andrew (ex Moore Eng Employee)
P.S. - I am loving the sunshine in QLD!!!!