Moving the remote needle valve further away: The longer the fuel line is from the needle to the carb the longer it will take for a needle change to take effect and the greater chance you have of the mixture changing due to flight orientation, g's etc. These little engines, with a few exceptions, don't have fuel pumps and only use venturi suction to draw fuel. Really, the most reliable location is to have the needle valve on the carb. The remote location is the result of someone sticking his finger in the prop and a lawsuit.

If you want to try a longer remote location, K&B makes an excellent remote needle valve assembly that comes with a mounting plate that you can locate anywhere. I use one on my OS .91FX. I never could get reliable running from the OS one on the back of the engine. You can leave the OS one in place and hook to the K&B one for testing, returning to the OS if your long remote doesn't work well. Search for K&B or Mecoa. They run about $15.95.

Finally, be careful about cowling an engine too tightly until you get a calibrated ear and can tell a lean run. Air cooled engines can overheat quickly. You will need a minimum of twice the outlet area compared to the air inlet area.