I guess we didn't get the memo telling us of you and your friends' capabilities.
There's learning, and then there's learning. You may feel you've mastered the first, but it's obvious you need to work on the second.
Every so often someone pops up on one of the construction newsgroups and wants to do something similar to what you are contemplating. Invariably they get the same advice. The curious thing is that the replies come from many different people who are pros - engineers, architects, experienced contractors, etc. - it's not always the same people spouting the company line. Invariably, if the response isn't quite so rosy as the OP hoped, the OP's response is, "What do you know?!" I find that amusing.
Ummm, no, those strips won't triple the strength of the trusses. They may strengthen the chords, but chord strength alone does not make a truss. Wherever you got that information, don't go back there for more.
To the problem at hand: If you're in an area that requires building permits it's a sure thing that the building department will require sealed drawings. Since you have some engineer buddies, that shouldn't be a problem. I'm sure your buddies are up on the major code revisions that were implemented in the last few years, and if not, are capable of coming up to speed. I'm sure that they'll also realize that it's not the member strength but the connections that will be the Achilles heel of your modified truss design, and that adding intermediate supports to a truss that was not designed for them can create localized stresses that are beyond the capabilities of the original design. A quick way to make your attic ground floor accessable.
Everyone approaches such remodeling in different ways. I'd have to see the roof structure to make up my mind for sure, but from my understanding of your description, I'd be more likely to wait until the roof is ripped and add new trusses at that time. You'd have all of the roof work done in a day or two, as opposed to many days or weeks, you'd have a designed solution, and you'd have new sheathing. I'm sure your buddies pointed out that the sheathing will almost certainly have to be replaced as it will be undersized for the new load. Smart people keep up with current events, and a couple of EEs and a PE will have commented on the major changes in construction techniques with respect to wind loads, uplift and required metal connectors due to recent hurricanes. These things are a pain to deal with while you're lying flat on your stomach reaching into the eaves, but a snap when the sheathing is removed.
I think it's great that you want to do the improvement, and that you would like to learn how to do it yourself. These are admirable traits. Another admirable trait is to not dismiss the people you have asked to help you. It's kind of like insulting the waiter before your food arrives - not a good idea.
R