Agreed. Start reading on the last two pages and wonder why you don't have an answer.

As to the other, yes, the high and low needles work together, but do you have any concept of just how far trhe low needle impacts the high? With some carbs the low impacts the high out to a little over 85% of the performance range. This little beastie out to about 60% or so. So how will enlarging a low circuit improve an already wet condition? You can lean the high needle until it's closed with no assist to the low. The high needle has, at best, only a minor impact on throttle performance below 3,000-4,000 rpm. Say what you will, but I just ain't buying into the statement at all.