I personally dont think the half and half approach is worth the effort. It seems like you would waste some expensive material unless you mixed the perfect amount each time. Wait for good weather and maybe push everything into your back yard. Trying to etch one side of the garage and epoxy and then do the other side??
I think you guys are making this a lot harder then it is.
Anyone who is planning to use muriatic acid/hydrochoric acid (mixed with water in solution of course) to etch concrete or to remove grease/oil should also neutralize it before washing is down the drive or street.
Just use some baking soda sprinkle it over the wet surface after scrubbing the acid bath solution in and you are satisfied with the results. Scrub the baking soda in a little. You can check the PH after with ph strips from any pool suppy place. Ph of 7 is neutal and that is what you want before you wash it down the street. Otherwise you will etch everything down the driveway to the crub and beyond.
Will it rust no... Water is what causes rust so if it is fully dry you shouldn't have a problem with rust. unless the there is a lot of moisture in your area (maybe close to the beach???)
Dudes??? there is so much stuff about this subject on the internet. Get the facts!!
How do you know I know what I am talking about???