You want to take a photo with dim lighting, high shutter speed (to get the sticks and fingers), with a DA18-250mm. No way - Surtout ne pas essayer, ca ne marchera pas.
You need to consider alternatives:
- use your flash, or
- ask the musicians to be still when you shoot with the camera on a tripod and slow shutter speed, or
- bump the ISO to 32000 + high ISO correction set to strong.
None of the above are perfect, and a better lighting would definitely help.
Personally, I would recommend to use a faster lens. (I have the DA18-250mm and I can speak of experience. An excellent lens, but its weakness is the low-light conditions). You would be best to consider a fast prime lens. Like a 31mm f1.8 or better a 50 mm f1.4. A fast lens has a large aperture (low f) allowing more light onto the sensor and faster shutter speed. Hence, you would be able to achieve what you want without flash.
Hope that the comment will help.... Bonne chance