Vegas,
That picture of that ROTJ that JRX is very proportionately accurate and has the right details. I don't mean to poo-poo your current helmet, but a Rubie's is very inaccurate to begin with (see my modification thread for a breakdown of why) and while Evo has done a most excellent job towards customizing it, the inherent errors of the Rubie's still show through. What amazes me is that in a faraway shot it looks great, despite the flaws, but up close you can spot the flaws.
The only downside to the the helmet JRX posted is that it is so nice you almost end up needing to upgrade your costume to be as nice as the helmet, but if you participate in trooping or costuming with other friends, you may end up being the envy of everyone. Your robe and cape appear to be the Rubie's thin fabric, which won't have the right look due to the folds and the stitching. Don't go for just any cape with satin lining on fleaBay.
Lastly, you might want to hunt down artisanprops in the classifieds section of this website, as he makes one of THE absolute best codpieces. The thing that some costume vendors do is cut out a thick piece of rubber and put leather over it, and for the vertical slot they rely on the cutout. However, for those who've studied Vader, this is inaccurate.
Here's what Artisan Prop's codpiece looks like.
You can ask him for a ROTJ version if his ROTJ version happens to have some subtle differences than the ANH that I'm not aware of.