When we test 1500 gpm pumps, we use three (3) lengths of 3" hose to a 2.25" nozzle.

Although NFPA recommends three (3) one hundred (100) foot lines into a 2.00" nozzle and one (1) fifty (50) foot line into a 1.375" nozzle.
This is in Table A.4.3.2.1 in the apendix of publication 1911.

I come down to your testing site and the location of your truck and the monitor you use.

You should not see much difference whatever setup you use.

It comes down to pumping the correct GPM at the appropiate net pump pressure. The friction loss in the hose should have very little influence on the trucks ability to pump the water required.