ORIGINAL: Arceenut
DO NOT double the antenna back on itself. This in effect shortens the antenna. The folded back section will in effect cancel the signal received by the section where it is doubled. Let the excess hang out the back of the fuse. Do not fold or coil the excess at the RX for the same reason. The antenna should be straight from the Rx to the end, minor deviations are permissable such as routing the wire around the compartment, etc. Avoid running the wire near the servos or any large metal objects.
Yes and no....
You can put a 90 degree bend in the antenna w/o appreciable attenuation of the received signal.
You can also place a bend in the wire that reverses the antenna direction back, provided that you leave a sufficiently wide effective loop.
As you've stated you do not want to fold the antenna back so that the two lengths run parallel to each other closely, however if the lengths are say 3+ inches apart or more there is no problem. BTW: I do this all the time.
Coiling the antenna does NOT effectively shorten it, and is purposely done with base loaded antennas and some "short" antennas, however it does reduce the area that is most sensitive to the signals. Done properly a "coil" or a base loaded antenna only shows a negligible loss of signal strength if the effective uncoiled length remains the same.