Mac, those look ok, but when you go into Ace or HD, tell a clerk (if you can find one LOL) that you specifically need one to filter out the toxins emitted by fiberglass.
Also, depending on what you are doing and how big of a project it is, you dont need to use fiberglass resin with fiberglass mat or shredded glass. You can use non or less toxic epoxy. I am not referring to 5 or 10 minute wal-mart in the tube epoxy. I am referring to:
http://www.zapglue.com/New%20Pages/Zap%2030%20Min.html
You can find that at any pro-grade hobby store such as hobbytown, etc. When the epoxy or fg resin weeps into the mesh, they both accomplish the same thing. Epoxy forms a mechanical bond and fiberglass resin sometimes forms a mechanical bond and sometimes a chemical bond. Mechanical meaning it "grips" the substrate, chemcial meaning it fuses the two together.
My own personal rule of thumb is if its bigger than 2 square feet that I am covering, I use fiberglass resin, smaller, epoxy. That will save your lungs.
Yes, long sleeves. Yes, open areas. Yes please, preparation is the key to glass. Clean surface, have your glass mat cut or your shredded glass in a cup or two, wear gloves. Put a film of vaseline on any exposed skin that will be working near the fiberglass, say bicep or neck...
I have glassed for a while now. Prep yourself with a dry walkthrough as far as having your materials ready, think it through (measure twice, cut once LOL) and then go at it.
Sorry for the novel, just wanted to help.