Could be the "sparkle trail" are pieces that broke off at high altitude (and continued to break up) and are "flying in formation" with the main body. They will tend slow up more quickly because of the surface area to mass ratio is and hence drag relative to mass is much larger, creating the "slant angle" effect you were looking for.
A couple of Germans in the 18th century did triangulation measurements of meteors seen during a meteor shower and came up with a altitude of 100 km (60 miles) for the altitude at which meteor trails are visible, a number which has held up well in the modern era of radar and astrophotography. At 100 km the atmosphere is very thin and friction is a lot less than on earth, so the atmospheric braking is a lot less than one might expect.
Some meteors actually bounce off the atmosphere and continue back into space.
Now you got me thinking, could have been that way and I was just assuming they were *flaking* off the main body instead of flying in formation with it, interesting perspective.