90 inches is indeed the correct length !
I measured mine from an opened kit, as well as from the one original I still have flying.
You tape the streamer at the midpoint to the shock cord creating two 45" streamers that you roll separately and stuff in the body tube.

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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, TURMOIL, FIASCOS, and HAVOC !