Hi, with the standard autolube system the output mixture ratio changes depending on how fast the engine is running (less oil at tickover, more at high revs)
With a Polini sport kit you would want to premix at 40:1 with a high quality fully synthetic oil if you are going to do away with the autolube system.
It would be better to fully remove the oil pump rather than just cut the pipes as otherwise the pump will still be spinning but without any lubrucation which may cause damage.

It doesn't pump in a continuous flow, these pumps always pump the oil in 'pulses' so whilst the engine is running it will pump one small drop every second or so depending on the engine speed. If you have see-through oil pipe you will see the oil suddenly move forward 2 or 3mm (along the smaller pipe) and then stop before repeating the process every second or 2.