Just enough to allow it to wick into the cotton gauze filter and give a nice even color (which is why they use colored oil).
Which is less than you think if you use the non aerosol K&N kit. The excess will drip down over the cambelt chest and leave a heart stopping oil stain on the garage floor
As an old colleague used to say - "I learn from my mistakes and the good news is I've made lots of them so now know loads more than I used to...."
