Hello and thank you for your question. This is difficult to answer without pictures. The best way to answer this would be with an in-person consultation where they can go over your concerns. Keep in mind, all material will have slightly different color under different lighting condition. While it is possible to adjust crowns, if necessary, too much adjustment can weaken the integrity of the crown which can lead to future problems. Also, when the lab makes the crowns the color characterization is built into the crown, too much adjustment can potentially affect how the color characterization fits with the surrounding teeth. There are several steps in creating proper crowns. After preparing the tooth, a provisional crown (Temporary) should be made. Tooth length, size, shape, etc. should all be tried in the provisional phase and any corrections made then. The permanent crown is then made using the provisional crown as a blueprint in order to ensure that the final restoration (permanent crown) matches the shape, position and color of surrounding teeth to make sure you like the results. Ask your dentist to arrange a meeting with the dental technician, it is really helpful if the technician can see the result in person. Another good alternative is getting a consultation with a Prosthodontist, who is a dental specialist who has advanced training in restoring and replacing teeth and can create a customized treatment using the latest techniques in dental crowns.