Bart, are you suggesting to turn the needle around because the engine is in the inverted position in the Nobler? If so, this won't be a problem at all assuming you put it back into the case the same way. The hole in the spray bar should point down the venturi correctly. That assembly has one hole on it so it makes it slightly difficult to see how its orientated. Take note how the hole is on the spray bar by looking at the flats on the hex nut and reinsert from the other side. I like the Brodak needle but be sure to see that the needles is closing all the way. I had a few that were real tight. This required me to remove the locknut and clean out any burrs where the spraybar  is split for the collet. I oiled the needle and worked it in several times to make sure it was closing down enough. Don't jam the needle closed as this could do damage.  My son flies his Brodak.40 using a APC 10x5. We never had to try another prop as this prop seems to be perfect with his plane. I know others have used the APC 10.5x4.5. That prop can be a little harder to locate than the 10x5. I've never run my engine using the stock muffler. I'm not sure if that is why my runs with the 10x5 have been so successful. I own an earlier version Brodak.40. The later versions so I'm told make more power. My engine though makes plenty of power with plenty to spare.   The engine seems to like to turn up a bit so I wouldn't suggest loading the engine with heavy pitched props. Fuels can be another factor here. I feed ours Powermaster 50/50 in the 5% brew. Ken

  I see that you are concerened with the orientation of the hole in the spraybar after turning it to the other side, what I have found that works to mark, with a notch in the spraybar where the hole is, then you can see where it is when in the case.
  Hope that this helps, and as to awitching to the other side that is what I did in my ARF Nobler, keeps from burning my fingers when setting the needle...

That will work sometimes, BUT... many times the run is not the same and the motor will not cycle as it did with the NVA in the other direction if using on a built up plane, Profiles are OK

Randy

Let me add that the Brodak runs real well if you place the hole in the spraybar at the 3 or 9 'o clock position rather than straight down at 6 'o clock. Just something to try if it's not running the way you want.

You are running it way too lean. With that prop RPM should be between 10,200 -10,600 rpm.  12,000 is more like the RPM you would get with an LA 25 and a 9-4 prop. No wonder it is overheating. Wrong fuel also. Powermaster 10/22 works well however I spike mine with an additional 2 ounces per gallon of castor oil. 
Recently I have switched to a one to one blend of Powermaster 10/22 GMA blend and 10/29 GMA fuel (thanks for the suggestion Mark and Fred). With that blend I get  a steady, strong run. The point is the fuel you area using has too much synthetic and not enough castor.  Other's mileage may vary but I stand by these recommendations based on recent, real world observations and experiments. For the record, 10/29 is no longer available from Powermaster however 10/22 is, as is fuel grade castor oil. And yes, it will need quite a bit of running in. Brodaks are like that.

Stock venturi is large, about .305". Still, it can work and many fliers use it as is.  Mine are downsized to around .285" either by replacing it with a Jim Lee venturi (see vendors section) or drilling out a venturi from a Brodak .25.  Stock NV will work fine, a Randy Smith NV will work better.  Stock spray bars sometimes have a burr on them which can prevent them from closing all the way. Check to see if your NV is closing all the way by blowing through the spray bar while closing the needle. If  it doesn't stop the airflow, clean up the burr  and try again, an easy fix.
Previous prop recommendation is good I prefer the Billy Clubman 10.5 x 5 prop. I would stay with your higher castor oil fuel despite the higher nitro content. As I posted earlier, Brodak 40's like more castor especially when they are not broken in. I'm out.