tintin,

Try ten (10) passes on the 5k using stropping-like pass (spine leading), then proceed as normal on the 8k.

Sometimes the light relected from the edge is a 'micro fin', and the stropping pass should remove it.

There are some discussions on the InterWeb about removing the existing edge entirely (gentle pass of edge accross side of fine hone), then re-cutting the bevel into 'fresh steel'. This is a bit contentious and mostly seems to be related to knives, but you never lnow !

Might be worth a try, and any experimental data you get would be most interesting for us

Good luck !

Have fun

Best regards

Russ