I have been germinating the seeds by placing the washed clean seeds (still in husk) in a plastic lunch box -- layering the seeds on top each other -- sealed with lid, in the old O'Keefe gas oven with a small pilot light. I think it's about 85F with room temp around 75F. But for the last 7 days we had the heatwave and my kitchen has been in the upper 80s and so I think it must be over 90F inside the oven, but the seeds love the heat and sending out roots very quick. (I was concerned about the high temp and moved the box out and on the counter, but the seeds slowed down.)
Every couple days I removed all the seeds, wash them in cold water and checked the condition. Washed the container also to minimize mold and fungus.
We know the mango trees don't like when it's above 90F, but the wet seeds love the 90F environment as I had learned in this experiment. When the roots were about 1" long, I placed the seed on the soil surface (in an empty orange juice or milk paper box filled with soil to the top and have a few drain holes cut out), covered the roots with soil but left the seed uncovered. When the seedlings are about 6", I cut open the bottom and plant the paper box in the soil.