Hi and welcome to the site. Congratulations on the new World. It's a fantastic watch and I know you will enjoy it.
Breitling Japan has a website that allows you to mix and match pictures of the watch models with different bands and straps.
http://www.breitling.co.jp/fitting/ and that may aid in your decision.
As far as a fair price, the last published MSRP quote for a Navi World on SS that I have available (keeping in mind there has been a price increase I believe since then) was $6800.00. (Croc strap with steel deplopyment buckle is $720.00.) You can usually expect a discount of ~20% off of that at some US AD's and some people do better than that.
Hope this helps and enjoy your new World.
Elwyn