[trowUrillioth]

Using multiple sources is a popular approach, but what I'm not certain of is where the Dhamma of the Suttas is seen to be deficient enough to warrant going afield. Right View is the foundation of the whole thing, and I do not see Right View any place other than the Dhamma; e.g. samadhi from other sources isn't going to be sammasamadhi.

To the extent that a sutra or other meditational/philosophical source deviates from sammaditthi (Right View), to that extent it will mislead and distract from the goal, and to that extent it should be set aside as irrelevant to practice.