You are right about the difference in the belief system. My intention is to recite the mantra for a purpose. So, based on what you said, I require initiation, which is ok with me. That said, I've also learnt and recited Rudram and Durga Saptha Sloki without any initiation. I just prayed to Lord Shiva to help me learn correctly.
There is still a part of me that says, just continue praying to Lord Shiva and learn SapthaShathi as well. But, I've read, not only in this forum but other websites as well, that it is dangerous (might lead to death of a family member) to learn without a Guru. Because I don't know how far that is true, I've held back. It is also the reason why I'm checking with a couple of senior boarders here.
Just FYI...I'm not playing with any mantra.
Thanks.