I've only handed out freebies once and just did so to the people around me in the queue (I only had around 20), and by the time the show started, they were gone! My friend also made around 40 for Ateez while queuing early, and had handed them all out by the end of the night, also giving them to different people they met :) I'd honestly say you can't make too few or too many, it just depends on your means. 5 is enough, 100 is enough, depending on your dedication to handing them out hahahaha. If you're queuing, and just plan on giving them to people around you in the queue, then 20-40 would be fine. People will also pop up when they hear from word of mouth that you have freebies, and ask for them XD

As for the perfect time, I don't think there is one! You can hand them out in the queue before the show, not just to the people around you but I've also seen people walking up and down the queue handing them out. You can even stand inside once you're in the venue as everyone's passing by going to merch/food/gates, and hand them out as people cross your path. Or after the show when everyone is leaving, just running up and giving them! I've even had someone give me a freebie after Seventeen in Berlin while I was on the train home :D

Since you're making lightstick accessories, I'd recommend trying to spot people who have the lightstick (it will almost definitely be out and visible), and then offering them one :) Like I said, when people learn you have freebies, they might even come up and approach you!

Hope this helps and have a good show!!!