My biggest concern is that it be the true gospel.
For example, in Kolo's example, these men had a spiritual experience in which the felt enlightened. So have others. From Mahavira to the Buddha etc., they went away in a time of seclusion to attain enlightenment and came back with some sort of supernatural experience.
But, the experiences that they had fail the Scripture test. If the monks' experience doesn't, then great. But just because there is an experience does not mean it was from God (it could be from self or worse). It must be harmonious with the Word of God.
If the monks' experience doesn't, then great. But just because there is an experience does not mean it was from God…
How is this determined by what methods? I think you have no knowledge of their training and expertise. Your questions are akin to asking whether experiments at Fermi lab conform properly to the method of physics.
And in the case of the reformers, the philosophers closed the lab. IMHO of course...