I would definitely buy the helmet at a local store, and while you are there I would try on jackets, gloves, pants, boots etc… and just take notes of what brands fit you in what sizes. After that I would go to ebay and buy the brand of jacket you want, but a model that is a year or so old but still brand new. Thats what I did with my Shift Racing jacket, I just got my size, and then found a dealer on ebay selling brand new ones for 150 bucks when they are normally around $300. That should save you some coin.
~Best Beginner Motorcycles Admin