I've used a C5 on my SLT with great success. However, I now do mainly EAA and with my C90 (USA starbright rubber coated) I use my small sensor 224 and either the FR6.3 or the Meade FR3.3 or a .5 on the 1 1/4" ZWO adapter.
The camera is very light, but a C6 is over the rated loaded. Most of my exposures are less than 8 seconds.
Anyone using a C6 for either visual or EAA here (posting this on the Celestron forum also). Does it over tax the mount?