I agree. This would be tough. Anyhow, your build being already top notch, such minute details might not matter at all, and are probably best left out.
The stripes on the aircraft tail might indeed be very hard to paint, although they are regular and parallel, so that a careful use of masking tape might work. At such a small scale though, that's probably a job best left for decals, if any can be found in the aftermarket. For the blast bags, one way to address the issue might be to use a Rotring Needle Pen. It provides a steady ink flow, independent of pressure (unlike a brush), and since the blast bags are an irregular surface anyway, drawing a straight line with a steady hand might not be essential for effect.