Some questions about agent skills

[Spacehawk]

Hi!

I'm playing a game of DW:Legends as the Ketarov and I hope someone here can help me with some questions I have.
First, where does the spying + 50 bonus for the Ketarov apply? Does it just mean that my agents start of with higher skills? Second, is there any way to improve the concealment skill other than actually sending an agent in a deep cover mission? I have an agent that has concealment +35% (skill + trait bonus). The success chance is displayed as something like 85%, so it's slightly risky. (I don't think my target empire has very good counter espionage though). Anyway, I would like to improve that but it seems to me that the only way would be to wait and hope for more beneficial traits to appear.

EDIT: And what about Espionage/Counter Espionage skills of ambassadors, what do they do?

[feelotraveller]

Concealment skill can improve with other missions.  I usually use Sabotage to destroy easy mining bases and Steal Tech (or map) espionage missions to train my agents and sometimes concealment improves rather than the related skill.
 
I think that the racial bonus for Ketarov is applied to the chances to succeed at missions.
 
I assume that the skills of ambassadors effect the chances of espionage/counter-espionage against the empire which they are assigned to.
 
Changing the time a mission takes can be useful for increasing your success chances although the opportunity cost in number of missions attempted can be significant.

[Spacehawk]

Thanks!

I assumed the same things about the ambassadors' skills. But then I thought, maybe they have to stay in my empire to do counter espionage...sometimes the documentation of the game is a bit frustrating. Or I don't know where to look.