Do not develop loads with a mix of brass. In my experience, Remington .308 brass is heavier than Winchester .308 brass. The remington brass is, presumably, thicker and has less case capacity. A load safe in the Winchester brass might develop too much pressure in the Remington brass.
I've never used Hornady or Federal brass for .308 Win. I've never noticed much difference in quality between Remington and Winchester brass. I use Winchester more I guess because I've got more of it. Most around here concur that Lapua's .308 brass is the cat's meow. Of course it costs more.
Maybe others who know more will disagree; but I've always felt comfortable using a given load in lighter brass than it was originally developed in. Then again, I generally don't run real hot loads. But you need a good estimate of each brand of brass' weight. Don't rely on just weighing one.