Abu Dawud pointed me to this website of some Copts, called www.3lotus.com - I assume they live in the USA. This is an organization of conservative Orthodox Christians, united in St. Mark Evangelistic Association.
One section of the website combines a lot of information on the Quran. It lists the usage of incorrect grammar, wrong spelling, and loan words than were misunderstood by Muhammad. Have a look and see whether this is useful for you. It shows the mindset of eastern Christians and how they believe they can best address Muslims.