Mac, since this is your 1st ksu install - hire a technician who knows the system! You'll get the job done right the first time & some invaluable training too. It's more than just plugging in a phone (I've seen your other posts).
Look at it this way - How Much Is Your Time Worth?
How many hours do you want to waste posting questions here, reviewing responses to get the right answer, hopefully getting the right parts, possibly having to buy new tools, posting more questions about programming & wasting more time trying to get the phones to work correctly?
Don't get me wrong, I'm sure you have had plenty of instruction & training to get to your position in IT Mgmt. But this field of work requires a good telecom technician - he does this type of work every day.
I see this all the time with my customers. The "thrifty" business owner wants the IT-guy to learn how to do phone work, so I instruct him on how to setup a mailbox, for instance. A couple of months later he tries it on his own, but forgot some steps, and calls me back to fix his mistakes. Don't be penny wise & pound foolish. Hiring a trained pro for a few hours is always a good investment.
Good luck with whatever choice you make!