It's amazing how "slippery" hair can be! I really think that tie systems that go around the head/neck benefit from some sort of stretchy material as part of the attachment. I hope you find some 1/4" elastic. If you can't, finding something with lots of friction that you can slide over the strings - off the top of my head I'm thinking of a strip of that anti-slip drawer liner stuff - that you put a few holes in and weave the string in and out of the holes to give the string more surface area and more friction just in the area you need it. if the elastic over the ears works, that will certainly be easy, but you may have to fit the elastic to the specific head, not just do the "one size fits all" that the instructions say, if it needs to be comfortable for hours at a time.
We did decide that unless you are wearing a ponytail or a baseball cap or something, the strings simply do not stay put- they slide up and down. I really liked the tie design but it isn't working.
Please tell your mother I think she's spectacular also! I think it's really good to have a variety of sizes and shapes. The fitted masks are comfy, but can be more claustrophobic. The size and shape of the individual's face can affect the fit of either style of mask, so having a variety of sizes and styles for people to try is really worth it. I admit that when I sewed my fitted mask, I altered the instructions to make that nose piece a little easier also! That said, several people I've spoken with or written to have said that they find the nose wire *really* helpful. I suspect that how important it is partly depends on the shape of the nose. As I said earlier, the *best* mask is one that fits you and is comfy - we're all different - vive la difference!
My spectacular mother has been sewing masks. She started with the pleated style with much grumbling about how annoying they are to sew. I asked her to make some of the fitted style Craft passion pattern masks shown earlier in this thread.