One tip with oaks from experience is they really need their mycorhizal root fungus and original soil. If you can't plant them in that then I'd find a few oak saplings t and dig down 3 - 4 inches. You are not interested in the sapling, just the soil. Carefully remove soil near the roots and add it to the pot with your collected trees so that the introduced soil can spread its goodness to your potting material.
The other way I do this is to put a collected oak into a pot with an established oak. I slip potted an oak I'd had for years into a bigger pot which accommodated the new tree, and then added soil so they could grow together.
I think this is as important as ensuring the roots don't dry out which I suspect is the reason for the success of the bonsai4me technique. Oaks hate having their roots disturbed.