Hey there. Thanks for your reply!
Okay I just thought using the grand master sounded like a fun idea especially with orbital relay. I haven't bought any models except one pack of Grey Knights and one pack of Terminators (these where cheap at my local club)
My idea was to drop the dreadnaught off with the stormraven whilst getting a squad in the rhino up the flank.
The armies I would be facing mostly are Chaos,Space Marines and Tau, possibly Necron. So I wanted a well balanced army so I don't bottle neck myself whilst facing any of these armies.
Look forward to hearing from you

Regards