yes you can shoot right off the string. Provided you have the release rope on your release.( the way it comes from Carter ). The only problem you may encounter is eating up your center serving. The rope, whipping off the the string can begin to wear it a bit. I have found that I like to use the loop. I ( my opinion ) like to have my release right behind the arrow, rather than under it.I think you get smoother flight from the arrow.
When you say that you have a hard time on extreme angles, what do you mean? Are you talking about your body being bent up or down hills? If this is the case, I to along with a lot of others have this problem. You have to make sure you are bent at the waist and try not to change your form. I don't know if this helps or answers your question, but maybe someone else will put their 2 cents in. Good luck. Jeff