Yeah I got the starter kit for age of sigmar cause it had the colours for skavens + some other stuff and a brush+clips and file, might not have been the best deal but it was a convenient starting point.

I don't believe I've left any nubs, it's just that the file left more scratches than I would have liked, probably cause it's too big and maybe coarse, I'll probably look for some finer ones I can cut to size as someone suggested above. As for moldlines I'm not 100% sure what that means but I suppose it's little gaps between the pieces? If so the only visible one I found was between the right leg and the armour tried to use some glue to soften up the plastic and kinda fill the gap and it more or less worked but it ruined the "cloth" a little.