Yeah, looks good! To save your thumb you can always try increasing the pressure from your air compressor. Of course the paint comes out faster...
As far as the casting technique I have a working hypothesis: These models are made from dead aliens. Considering what I know of casting techniques and the Repo Man documentary, that has to be the answer.
Forgeworld should send you a free bane blade for promoting their product. I have been seriously considering investing in some resin and this post is helping clear the way to FW.