Dosing Traces (and other fertilizers) in a planted tank is a highly debated subject amoung Shrimp keepers. There are many that dose without any kind of problems and others that are quick to accuse ferts as the cause of sudden die offs that they have experienced. IMO
you need to do what you feel comfortable with when it comes to the health of your shrimp, keeping in mind that if this means cutting back on ferts it could be harmful to your plants.
I've currently got a High Light 10 gallon tank for breeding Cherry Red Shrimp. I dosing a full complement of ferts and have yet to see any problems with the shrimp, but I've only had them for a little over a month. Several are carrying eggs, but I haven't seen any shrimplets yet. It's really too early to be able to tell for sure. There have been sufficient reports of people keeping shrimp successfully in high light full fert situations, that I felt it was worth the try. I have been running the tank a bit lighter on ferts to help hedge my bets and seem to be maintaining a balance between avoiding algae, keeping the plants healthy, and keeping the shrimp healthy.
While Flourish Comprehensive and CSM+B do contain copper, there have been reports from more knowledgable hobbiests that the levels are well within the tolerances of shrimp if dosed correctly. You may also want to keep an eye on the foods that your are feeding your shrimp, as many contain copper as well. While some people have reported no problems feeding these foods to the shrimps others have reported sudden die offs. Another possibility that I'm inclined to believe is that it could be that dangerous levels of copper and other substance were probably reached through a combination of sources including tap water, fert dosing, and food. Since I keep a close eye on the food and my tap water is in pretty good shape, I feel this gives me more leaway with the ferts.
In the end the care of shrimp is new enough territory that you will need to make your own decisions based on your situation and what you are comfortable with.