When I saw what you were shipping, I immediately knew your problems were different from many other shippers. Shipping pillows can be a nightmare. The good news is you are not the first company I have dealt with that has this issue and maybe I can give you some ideas they used.
Light large objects mean that dimensional weight or oversize issues will come into play. Therefore, the first thing you need to do is to come up with standard boxes that optimize the amount you can put in the box at the best carrier prices. This will take some work on your part but will pay off big once completed. Reviewing rates across multiple carriers is highly suggested and be sure to look at them for all zones.
You might also look at ways to compress your pillows in packing, if at all possible. Since you are shipping pillows consider using recycled paper and strong boxes for packing material rather than environmentally friendly packing peanuts. In most cases weight and/or damage from dropping is not your issue. Instead you need to figure out how to get the most you can in the smallest box as possible.
Once you find the right combination of packing, box size and volume you will be able to have a known shipping amount for price quotes. I believe giving the price based on how many boxes you are sending at known shipping amounts rather than trying second guess variable oversize costs will give you the edge you are looking for.
I hope this helps and you sell a bunch (in the right boxes that is…)!
Bert at Harvey Software, Inc.
Multi-Carrier Shipping Software and Supply Chain Solutions for Internet Retailers
Also a provider of free shipping information and resources at Harvey Software`s Parcel Shipping Blog
along with free tracking solutions at TrackingPage.com