Duragloss, in my experience, offers some great value for the lower costs. From a business perspective I look for lower cost but higher effectiveness. I also buy in bulk for the highest turnover products I use thus lowering my per use costs.
I also agree with cstmsprty on 3D/HD products .
I've also looked at my operations from a "movement efficiency" perspective and use a cart to minimize as many unnecessary non working walk arounds as much as possible.
I know, Bill, these are not directly addressing your great questions but just some personal things I've looked at to reduce costs and maximize efficiencies.