FWIW ....  one of the companies I used to guide for had a yearly flare training at a local Coast Guard station.

We tried to sample a large array of the commercially available “kayak size” flares ..... unfortunately the results were extremely disappointing. The brand new flares had about a 80% success rate, but any that had been schlepped around in dry bags for few months had a less than 50% chance of working. We had much better success with the larger sized flares with almost 100% with new and 75% or so with those that were well travelled.

I still think they are a good piece of safety equipment ... but you either need to carry a bunch of them or have them as overlap with other signaling devices. The CG highly recommended a cylume sticks on string swung in big circles as one of the smallest and most visible signs for the helicopter to see.

Maybe you could bring your old ones to GS5 for a test ? .... the CG is usually OK with test shots as long as you call and give them a heads up