IMO one thing that helps is to come prepared when you go in to order. In that I mean, probably print out the catalog page with the ordering matrix for the luminaire you want and also write out the full ordering code of exactly the config you want to order. Most places will probably appreciate you did that so they know exactly what to order.

The local place I go to for more specialized lighting stuff is like that, you can't really browse but if you tell them exactly what you're looking for, they'll gladly sell or order it for you. They mostly sell to contractors but are also open on weekends and cater to homeowners. 

I've always done that. I write down the ordering code I want from the manufacturer catalog and call or email the distributor and give them the ordering code. I actually just recently started ordering a few things again and set up a contractor account with a credit line at one of my suppliers. Which will make it much easier billing for shipping charges since they just bill me for the fixture and shipping when they get the charges and I pay later by the due date. Paying by credit card in the past is not easy since they don't always have the shipping charges ready when the item arrives.