Question about Raptor Imperialis

[Lautrec the Embraced]

I've failed to find meaningful information on the web about how does one qualify for the Raptor Imperialis mark (eagle's head). I'd be much obliged if you could enlighten me.

As I understand, it used to be a symbol of the Big E in Unification, but later it became an honour badge for those that had fought "alongside the Emperor".

So, uhm, what does alongside mean exactly? In visual contact to him? The same battlefield? On the same planet during the Great Crusade? Metaphorically alongside? What are the criteria?

I intend to start a new, loyalist army of blackshields and am unsure how many Raptor marks should I allot and to whom. Very few, only for Unification/Terran veterans? - or treat it as a mark of allegiance and give it to every other guy? Maybe some variation or other marks (lightning bolts?) could signify ...something...?

Edited 1 hour ago by Lautrec the Embraced