Orthodoxy vs. Progressive Christianity

The primary doctrines of Christianity may be stated slightly differently from one church gathering to the next, but they are the ones that, by and large, we should all agree on. There is clearly a large measure of grace that we are meant to extend towards one another as we are each pursuing Christ with a limited ability to fully understand many of the big topics found in scripture – so with that in mind, if there is a big disagreement on primary doctrines, how far is too far?