I am using both Developer (aurora) and release versions. I am using a Hurricane Electric 6in4 tunnel for my IPV6 functionality due to Exede's delays in IPV6 implementation. The tunnel terminates at my ASUS RT-AC3200 running ASUSWRT Merlin so IPV6 looks native to my systems. IPV4 and IPV6 only sites work fine but I suppose due to the tunnel delay, most dual stack (IPV4&IPV6) sites load as IPV4. I believe I should have the same experience as a native IPV6, which I have seen on my daughter's Comcast connected systems, but this is currently not so. I think there should compensation, preferably configurable, for the tunnel overhead so Firefox's behavior no longer looks like it prefers IPV4 but IPV6 first. Is this not possible?