New garage-floor covering....

Sorry I keep thinking of more tips
When it comes to the flakes, before you start, lay down a piece of heavy plastic about 4x8 and practice laying down the flakes, that way after you get the feel for it you can pick them up, because when its painted once they're down, they're down, I've thrown them in the air, I've even heard of using an old parmesan cheese container like a salt shaker
If it has cinder block foundation around the edges of the floor, and you don't want flakes on the block, mix up a gallon, paint the cinder block first, let it dry, then do the floor
With a garage that size I'm sure there's plenty of expansion joints, cut and roll one section at a time putting plenty of paint in the expansion joints
When you etch the floor, mix the solution up in a 5 gallon bucket, if you have oil spots on the floor, scrub those spots first, with the floor dry, then wet the entire floor , and scrub it, you can also use a rag MOP to distribute it then scrub, don't just dump the bucket on the floor, and before you rinse it, wet down your driveway good first, and keep wetting it down as you go, otherwise you'll etch your driveway also, and you don't want that, rinse your garage floor well, you cant rinse it too much, but you can not rinse it enough
Once its all dry(at least a day) right before you start, use a leaf blower to get rid of any dust or debris that may be hiding, close the garage door all but about 2 or 3 inches, ( this will keep out most blowing leaves, stray animals and neighborhood kids) open the windows, and use a respirator, epoxy is some strong stuff, and the price of a respirator($30) is worth the brain cells you'll loose otherwise
Tomorrow I'll ask my boss what we use in heavy duty industrial jobs, machine shops, heavy forklift usage etc and let you know
Again sorry for so much info and tips but that's what I do for a living (general residential and commercial painting for the past 30 years) and I've done probably 30 garage floors and a couple factories