I typically don't use Oxbow's products, but I can give you an idea of what I use and why as far as hay is concerned.
I always try to add variety to my rabbits' diets. They different types of hay, in manycases,offer a diverse selection of nutrients as well as wearing down their teeth differently. My belief is that offering multiple types of grass hay is extremely beneficial to their overall well-being and health. I use timothy as my base hay and purchase it in bulk from one of two companies online. I then have at least two other types of hay on hand at all times. What works best for me and my buns has been orchard grass and oat hay (which I recently began feeding). I've found that offering different types of hay my rabbits actually consume more and that's better for them all around.
And I know I said that I don't use Oxbow, but that's not to say that it's not a good company. For me, there were some issues that were raised after feeding their products for quite some time. Also, the shipping costs were exorbitant for me since I'm in Ohio. Even ordering from other catalogs such as the one you're ordering from was too expensive to suit my needs. Therefore, I use two companies that are based on the east coast - Bunny Bale (for bulk hay) and Sweet Meadow Farm (for pellets and other hays - but I may be switching over to this company exclusively). But, as I said, Oxbow is still very highly recommended - it just didn't work for me and my rabbits.
I'd definitely suggest getting the timothy hay and then getting maybe a bag each of some other types of hay to see which ones your bun likes best. And then go from there...