I too believe that you need to remove all the coarser striae. However, as I said above, the Shapton 8k HC makes a smoother and more mirrored - fewer observable scratches - than the Pro but I cannot tell a difference in the feel of the finished edge. This may be because I follow each with koma and tomo which are or can be fairly abrasive, but I would be skeptical of a finished edge with 1k or midgrit scratches.

Shapton designed and graded the Pro series kind of as 'coarse, medium, fine' while the Glass series, both HR and HC, are designed to double in grit (though they make a 6k too).

So my progression for a razor needing serious work would be Shapton Glass HR 500 and 1000 for the coarse work, Shapton Pro 2k/5k/8k for the bevel set, midgrit, and finish prep, and if I wanted the Shapton Glass 4k HR could stand in for the 5k. Anyway, this is an approximate doubling of the grit at each stage, and my normal synthetic set is only 3 stones, the 500 and 1k are not often used.

Cheers, Steve