I'm obviously still not awake. ThanksYou don't need to use Nikwax TX to reproof since it is living on the inside of your roof. There will be no water spraying directly on the fabric and the coating/laminate is waterproof by design.
Since the thing is not dirty, only smelly, I think jus a little amount of detergent will do.
And like tents: storing it for longer time? Put it loosely folded in a cotton bag (pillowcase perhaps) and store it in a dry and well ventilated place.
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