Temp and RH? IDK...whatever the room is. They're vegetables, they better be able to take differing temps and humidity. Its like 72* in here now, but I'll let it drop as low as 62 at night. I figure if the weed doesn't care, the tomatoes certainly won't.
I use the same period as my autoflowers, because they are in a tent with 2 of them. 18/6.
I'm just using masterblend and then coco for the medium to put the seed in, in the seed cup. Coco does kind of dirty up the reservoir, but it does the best job at blocking light. Plus its really easy to sprout the seeds in. I'll be skipping little seed containers next year and just germinate straight in the net cups.