Jets and needles are not the same thing. For driving mixture the 32/36 has jets (brass fittings with specific sized orifices - the jets can be changed to change the mixture) but have no needles (as used on SU an Stromberg variable venturi carbs where the jets are a fixed size and tapered needles move up and down to meter the fuel--the taper of the needles determines the mixture and they can be adjusted or changed to change the mixture characteristics) for driving mixture.
Adjusting the Weber idle mixture does involve the one "needle" in the Weber--the mixture screw is tapered--turn it in and the mixture gets less fuel (leaner)--turn it out for more fuel (richer). This will not help your driving mixture--but may help the idle.
I think you should look to pick up a Haynes Weber manual. It will help you understand the functions and get you familiar with the terminology. The extensive charts of jets for production cars with Weber carbs may help you understand some of the relationships between engine size, state of tune (is fuel economy the goal--or performance, etc.)
Sorry if this is confusing--carburetors, while simple in principle, are complicated subjects. -- Dave