across the top head left right ,left right
up & down from left frame to right & back
then zig zag down top to bottom
i use a john hewitt 505 backpack on the slowest flow, i dunno what it is in ltr/min but its faster than a sureflow bp middle setting
when i first started i was rinsing a lot & i couldn't see why i needed to lift the brush off so i never did, no idea if the brushes i was using were flocked or not ( a vikan then a brodex)
using gardiners sill dual trim for last 2 yrs gradually i started rinsing less & less. obviousely sometimes i get bits on the glass but another zig zag down always gets them & if i'm going round a corner & i cant see the glass properly i sometimes give it a spray or for juliet balconies & i've never had a complaint about bits left on the glass.
yesterday i tried a gardiners dual trim superlite for the first time & that seems even faster to zigzag well happy with it