If you're sending your kids to daycare like we did, they need to have all the bottles made and ready for the entire day. This meant 2 kids, 6 bottles/day while at school = 12 bottles to make. Every day. Just for school.
So don't kill yourself making each bottle individually. Go get yourself a couple of pitchers. You can get them anywhere. You used to make strawberry daiquiris in them before you had twins, remember?
Make sure each child has his own pitcher and write his name on it so there is no confusion. The last thing you want to do is mix up the formulas. We had 1 child with a milk protein allergy so he was on Neutramegin, which was one of the most foul smelling odors I've ever smelled. I still can't even believe he drank it, but he did. The other one was on Enfamil AR, which is pretty common.
Mix the right amount of formula with water so there is enough for all 6 bottles. Do this the night before and put it in the fridge for the morning. Pour the bottles in the morning and you're good to go. Before going to bed that night (obviously after washing all 12 bottles and the pitcher), make the pitchers again and put in the fridge.
While it doesn't seem like much time is saved, believe it or not making the pitchers and not the individual bottles saved enough time for us to maybe eat breakfast in the morning or perhaps snooze once or twice.
And in the world of having children, not just twins, those two things are gold.