I think you should wait but i dont know for how long.
If the feeder store says 1 week, i would wait 2 weeks at least, if the instructions say 1 week, same.
There are several ways to try to control the worms naturally but there is no natural way the birds can get completely clean. Some people use those remedies in between the dewormings that are suggested to be made every 6 months no matter if you see worms or any reasons to deworm them. Thats what i have read in here, make a search there is plenty of information here.
Some of those remedies are:
Raw garlic cut in pieces and fed to the chickens or keep it in water overnight and give the water to the chickens, some people always give garlic water.
Hot cayen peper seems to mess with the worms house and makes it uncomfortable and some may get out of the bird.
Some specific seeds that i cannot recall right now are also crushed and given to the chickens, i am sure somebody else will tell you more.
But keep in mind that those ways will not clean an infected bird, they will just control the population of the worms.
If you MUST use a dewormer, then use it to save the bird...i hope i will never have to use dewormer but i will propably have to do it eventually sometime....
Little advice: isolate the bird for few hours or overnight, then set it free and watch the poop very closely, get a small stick and mess with them, if you see a worm (they look white, i think, and not too much like worms) that will mean your bird has a big infection and the worms are so many that some come out.
Thats all the advice i could give as a fellow newbie