Help with making meringues!

I'm referring to the cookie. However I also need help with getting egg whites to meringues (stiff peak).

I have some questions about it and here they are....

How long to beat to reach stiff peaks?  I'm referring to time required with BOTH room temp egg whites AND cold egg whites (from fridge).

Can I use cold egg whites?  I know that room temp. is recommended, as it reaches meringue faster than cold. However aside from it taking longer, is there any drawback to using cold egg whites?

Mixing bowl problems. You use clean and grease free mixing bowls.  My bowls are clean, but have a cloudy film from hard water deposits and can't get rid of it, I've tried.  Are they still considered dirty due to this?

What size bowl to use? I know this depends on how many egg whites; however I just need general guidelines (i.e. for every 2 egg whites use 2-qt. bowl, every 4 egg whites, use 2-qt bowl. etc.)

Help with bowl sizes.  Guidelines I have found  recommend for 3 egg whites, use small bowl; for 4 or more, use lg. mixing bowl.  However with qt-size. what is considered 'small', what's considered 'medium' and what's considered lg? (i.e. small mixing bowl=2 qts., medium=4 qts. etc)