I like Glass Gleam 4, since I have to deal with hard water here in Central Texas. I buy it from Dallas Window Cleaning Supply. You have to keep the water clean though--if want to use the same bucket for a big job, nothing beats Dawn. I know another co. in our area that uses Dawn and a bit of vinegar, but I don't like leaving that smell around on my good accounts. I only use vinegar in the mix on residential exteriors that haven't been cleaned in years. My wife complains about the Dawn taking her skin off! She is free help, so I have to accomodate her...but I use Dawn when she isn't around.
Be careful asking for actual bid prices or prices per window--this can be construed as price fixing (a crime!) The best way to come up with a price is to go and look at the job. Look at what kind of junk is stuck on the windows, sloping landscaping, mud, dogs that grab your rags and pee on the ladder, furniture in the way, etc. Then add $ for everything that looks like it is going to be a headache--like screens that are screwed on on 2nd and 3rd story windows--you WILL drop screws that cannot be found. Make sure you add extra for ladder work.
If the customer doesn't like your bid--don't go down unless you deduct some work. Like, "I'll deduct $30 (or whatever) if you don't want me to open the windows and clean the tracks." Don't give your work away! You won't be able to get your full price on all the word of mouth from that customer. Don't ask me how I know
Then when you get done with each job, figure out how much you made per man hour compared to what you want to make. Doing this each time will help you bid in the future. Under-bidding a few jobs will help you look more closely on the next window count!