Thanks for looking at this and replying.
I will most certainly look into the mass of water/ME' Scope issue. I am curious about this as well. The guy we've hired to do this testing is one of the best at Modal/ODS that I know of and has years and years of experience so I am the results we will get are as accurate as possible.
Like you said, we will be using a combination of coast down testing, ODS, and Modal data to try to narrow down where those frequencies are and how much they shift with and without water.
I will look into the ME'Scope possibility and get back to you. Will also share the amount we find the NF's shift with and with out water.
Thanks again for your help.