In such cases, there can be communication gaps when you work with a bigger retailer because of the volume they have to produce and you may not get what you really wanted.
Above all, price is a very important factor because paying more for something that is not worth that much is really a bad idea. Always compare the prices offered by different shops and go for something affordable. Approaching small shops might get you a better deal than the large facilities.
There are really no set rules in custom art framing and the only thing that matters is how your artwork will look in a frame as a result. The best thing about custom frames is that you have numerous options to choose from and a lot of time to decide on a design. So, make use of the opportunity and ensure that you have the best suitable frame for mounting your art and preserve it the best way possible.