Hi Jack,

 I would always try to work out a job bid rather than a per object or day rate. You don't know how picky they might get so you need to set some standards. I will produce x number of shots per day and break down all your costs so they can see them on paper. Then the creative fee is added to the costs of production. The creative fee is your part. I would also talk to them about usage rights, this is a good bargaining chip when you start to haggle over price. Do they want a buy out, it's gonna cost them. Do they want it for a single add spread or will it be on the tags that are attached to the glasses only. All the different uses cost them more in the standard commercial photography business. Most of all what are you willing to be paid, they will see it in your mannerism if you are to anxious. Hope this helps a bit, it is pretty complex when you get to negotiations with a big company. If they have 230 pairs of glasses then they are a big company.
 Then if you get the job make sure you know how to shoot sun glasses. They are very difficult quite often to keep the front glasses from reflecting the entire set and you in it. Try a bit higher angle so the front of the glasses reflect the seamless that is out in front. Let that front seamless run quite a bit out in front of the glasses to help and use a wide piece of seamless. A nice gradation across the front glass is always a nice way to add depth to the product. Make sure their side logo pops by adding a good reflector or white card at the appropriate angle then light that with a gridded spot as well with card behind glasses and off camera. Try bouncing a spot grid spot off the front seamless at an angle to gradate the front paper thus create a gradation in the front of the glasses. I used to shoot a lot of sun glasses. Now it's easy to keep them dust free in PS we use to use a lot of canned air back in the day. Hope this helps.

Best,
Jonathan