Tactical squad sergeant

For my tactical squad sergeant I wanted to go a little bit further with modelling something unique for the Astral Knights.  Firstly I wanted to give him a sword and shield, the archetypal knightly weapons, however a tactical squad sergeant wouldn't look right with purely assault weapons.  So I have put a small shield from the terminator sprue (I think) on the right hand which holds the bolt pistol, it provides no actual benefit in a game but it looks the part especially with the sword symbol on it. 

I may have gone a bit ott with the sword as I have used one from the champion set and it's huge but I suppose you can never have a sword that's too big.

You can't help but notice in the photo above that he has a 'plume' of feathers.  These are from an imperial knight WFB set and have been put onto a helmet that has a more medieval style face plate.  I really like the individuality this gives him, he stands out from the rest of the squad and I've never seen marines with this type of head gear before.

The only issue I have with it is making the join between the plume and the helmet look more 'official' and less converted.  Does anybody have some tips for greenstuff methods or something else that would make it work better.

I am still trying to decide if I want to add a banner to the sergeant.  He's got the height that makes him stand out from his helmet but I'm a sucker for models with banners.  So do I try the standard marine banner, hanging down from a horizontal crossbar, or do I try to model one that flaps out behind him from a single vertical pole, or do I leave well alone?

As always any thoughts, comments or suggestions gratefully received.