Here is the info I used off of N tractor forum:
I go ahead and put the econ jet in there. So far, all of the carbs I have rebuilt were already threaded for the jet. If not, it's a simple matter to run a 8-32 tap in the econ hole. Jet sizes supplied in the kits seem to vary widely in hole size. There are various recommendations based on what works for different folks. I know these sizes work:
Idle jet at least 0.032"
Economizer Jet at least 0.046"
Power Jet at least 0.043"
Make sure the related passages are larger then the jet sizes listed above.
Here is info from this forum:http://www.ytmag.com/cgi-bin/viewit.cgi?bd=nboard&th=712077