Never told my insurance anything lol.
Its strapped so not modified as far as I'm concerned.
I carry a 650, solo I use about 500 a day but always good to have a bit incase.
I don't mess about with flow, trying to save a few quid on water is a false economy. Controllers set to full, use as much water as you like, faster flow faster rinse, quicker I'm onto the next job.