Sharing my knowledge here - hopefully this will save some of you some time and effort. Here's a link to all the designs;
Make your own mask link
I started with the "Olson", fitted version. These looked the most comfortable but ultimately were more complicated than they needed to be - and weren't real comfortable. The do not slip - that's good, but they tend to open up at the top so your glasses fog like crazy. They are also much warmer than I expected. Worst part was though, unless you do a lot of sewing, and I don't, these are really time consuming to make.
Then I decided to simplify and went with the pleated version. These are MUCH better IMHO. They are far easier to make and are more comfortable, plus not as warm.
Now about the ties vs. ear thingys;
I do not like the ear thingys - at all, plus it is really difficult to find the thin elastic right now. No, you can;t cut down wider elastic - it unravels.
So ties...
You can sew ties into each corner, then tie it twice when you put it on, but don't. Do this instead; use a single 45" showstring and threada it through so you can put the mask over your head, then tie one end or the other once. See instructions
here, page down to "wearing instructions". That will give you a nice tight fit that won't slip and is the easiest way to put it on.
OK, so now all of that sewing in the rear-view-mirror, I would recommend buying the masks from
Score instead. We ordered some of these and I did the sewing while I was waiting for them to arrive. The Score masks are MUCH more comfortable, lightweight, cool by comparison, IOW, better in every way. I am modifying mine with eyelets in each corner so I can tie them, but otherwise, that is my best recommendation.