I have gotten to where I don't even worry about the loss of a well
constructed choking--balun/unun in the circuit--better to be safe than
sorry...

If the decoupling is designed into the antenna, using cones,
bells, sleeves, etc, there is little if any loss. Being as the
feed radiation skews the pattern up off the horizon, adding
decoupling usually ends up with a "gain" at that low angle.
Also, I've heard different types of "J" feed methods, naturally
decouple better than others..This also applies to the ringo's,
etc. The gamma loop matching device on a ringo does a
halfway job of decoupling the line, but it can always be improved
by a 2nd decoupling section. I don't use conventional ferrite
chokes when decoupling VHF/UHF antennas. IE: If I were to
add additional decoupling to a ground plane, I would use a
2nd set of radials, or a sleeve, vs a ferrite choke. MK