Personally I don't like getting anything metal or any other tools that close to a spinning prop. It's too easy for the end of that tool to wander into the back of the prop and then it's going to be propelled right into your hand. IMHO it's a lot easier to loose control of the end of that long rod than it is to let your hand wander into the prop. It's just my personal opinion from being around these engines a lot but I think you have made the situation more dangerous with your setup than if you simply adjust the needle valve with your finger. You're free to do what you want, but I personally wouldn't use a setup such as that as I don't think it's safe.

Needle valves such as this can be safely adjusted with your hand as long as you adopt a few safety procedures. The biggest of this is to NEVER let your hand or fingers to get any further forward than the needle valve itself. When I make these adjustements I come in from behind the engine with my hand even with the fuselage of the plane. Then I use my thumb and forefinger to turn the needle valve. My hand or finger never get anywhere near the prop this way.

Ken