I'm not sure how to paint my Relthorza.
I never liked the Relthorza studio paint schemes, as they did not scream 'wierd arachnid race' to me so much as 'grey with some mild pastels'.
The structure of the ships remind me of EVE Online's Rupture class cruiser, with it's metallic bronze hues.
Obviously I am not original in this - Martin from "Fire Broadside" has a nice version similar to the look I have in mind - only a little less metallic than what I envision:
I could go for a weirder hue - "spiders" makes me think of redback spiders. This guy has a few variations I might try (see lower down posts)
I'm surprised there isn't more variation - so many talented people tend to slavishly copy the studio paintjob for some reason...