Nice, congrats! Didn't even see he had that for sale.
For crest, something heraldic. Not sure how to do the iron cross or the sun, though. You aren't restricted to just that, though. For a "full" heraldry, there were animals and such outside of the "shield" part of the heraldry, so you have lots of options.
I'd check on the Knights Arts page for crests and see if he has something you like. Makes it easier to pick from a crest that you know you can buy, instead of picking something, then trying to find it for sale. The flip side is you have something other's might, but it's easier (and generally cheaper) to go with something already available.