Lightless lantern and horror marks

[Amhazair]

I never used a lightless lantern in my SP games (too much micro ), but I'm currently in a position to produce them in a multiplayer game with Ulm, and I'm looking for some information on wether they're worth it.

First off, they cost 5 fire gems, which with master smiths and dwarven hammers becoms the ridiculously low amount of only 2 fire gems (and one mage-turn) for a 6-point reasearch bonus.

But then the problems start: according to the manual the lantern gives a 'slight chance' of a horror mark. Which doesn't say too much. What is a 'slight chance'? 1%/turn? 10%? 25%?

Then, once a mage is horror-marked, what are the chances of a horror showing up? (I never actually got to see a horror in any of the games I've played yet but then again I only just started to MP, and never used any spell or item dealing with horrors myself ) Can you expect one to show up in the next couple of turns, or is it quite possible not to be attacked for longer periods of time?

Then, if you are attacked, are there any ways to actually survive the attack? (It would most likely be Master Smiths facing the horrors, I have no brilliant survival ideas - not efficient ones at least) Would scripting an astral mage to cast returning save his life? (I have access to a couple of astral mages, but they're more expensive and less plentiful than my smiths - and if the horrors attack often this could quickly start to drain me out of astral pearls)