Sounds great!
I don't recall the details if you had a previous topic on this subject, but what type of windows do you have installed as the prime units? If they have a low-e coating on the glass, you are going to need to vent those storms in the warmer months to prevent excessive heat build up. Unfortunately that will pretty much negate the improvement in sound transmission.
Additionally, you will want to check on the warranty of your prime units, as for some manufacturers the installation of a storm unit will void the warranty automatically.
Don't mean to rain on your parade, hopefully your situation differs from those circumstances. Just thought that I would throw that out there before you invest in a house full of storms and end up with other problems.

Great follow up.

Airspace - Mass - Thickness = Better STC

Homeseal - thanks for the information. Truly appreciate it... I do not know the answer to your question so a good follow up for me. They do have little vents in them but I assume this is for moisture run off. For the warranty side, I think the prime windows are honestly of such mediocre quality not sure it matters but time will tell.