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Slight apples to oranges considering our engines are vastly different for several reasons, but a 42 pilot is pretty darn big. I run a 38 with a cam and port work with a full exhaust. But, that is again apples to oranges given our different engines and mods, so neither here nor there.
Also, as aggressive as the needle taper is on the PE carbs out of the box, being all the way in the bottom notch is impressive. I am in the second notch lol. Admittedly, my main jet is quite big compared to what you are running, so that plays some factor, but even most near stock engines I know of don't go below the middle notch.
My method for getting a carb figured out is to first start with the pilot jet and have the needle in a neutral position (3rd notch). The main reason why is to try and eliminate variables. I actually adjust the needle last.
I figure out the pilot jet by first sorting out the idle mixture. This can give a clue into the pilot jet being potentially big or small. The 2 turns out is promising, but it never hurts to verify. With the engine up to temp - having run at least 5+ minutes - I will check and set the mixture based on the idle drop method. Simply turning the air screw in 1/4 turn at a time to richen the mixture until the idle drops off. I then back off 1/4 turn to the last adjustment where a steady higher idle was present. If you want to go a bit leaner you could back off another 1/4 turn, and as long as you don't get any lean symptoms like a hanging idle, this is a good range to be in. Generally, I aim to have this adjustment more than 1 turn out and less than or equal to 2 turns out.
Once that is achieved you can actually test to see if the pilot jet itself is lean or rich by simply riding the bike in a steady off idle to 1/8th throttle position (trying to keep the needle out of it). I find puttering around my neighborhood in second or third gear on flat ground at 10-20mph is a good way to achieve this. If it hesitates and bucks a bit, it's like too lean. You can always hold this state for a fair amount of time and do a plug chop to read the plug if desired.
Once you have that sorted, we gloss over the needle and do the main jet. We do this, because like the pilot on the bottom end of the throttle position scale, the main jet is the single biggest factor on fueling past 3/4 throttle. WOT plug chops are the poor mans best way of reading main jet fueling state.
Once you know for sure the main is a good size, then you can determine and make needle adjustments. The reason why? The needles fueling curve is greatly influenced by the main jet. I run a 135 main jet on my bike, which is a good bit bigger than a bike without all of my engine work, so the part throttle fueling on my bike is a lot richer than another persons might be. That is why I have mine in the 2nd notch.
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