My REI storm matches came with a pair of extra strikers in a heavy plastic sleeve. I trimmed my matches and the cut the striker off the box and put it into my K&M matchcase. The extra striker was thick and took up quite a bit of room so I elected to use the box striker. The striker is away from the matches facing the matchcase wall and there is no movement inside the case.

My experience with nalgene bottles is that they seal very well. I may have to go look for some of those bottles.