If you've got a bulge in your hose, the hose has got a hole somewhere, which shows under pressure.
With my 100m minibore, I've got the shutoff pressure at 7, and flowrate 2, equates to about 1.7lpm at the brush head, but I need to fine tune it. But it works for me, there is no initial brust at the brush, and steady and even flow. I haven't checked yet how the pump cycles or anything like that, but it shuts off relatively quickly. Always make sure you lay a good amount of hose out, there is more backpressure when the hose is coiled up at the reel.