The different information you are getting is just a result of different schools of thought. Some people like to have it blow off and get rid of the kreusen, some don't. Both is just a matter of preference, your beer will be good either way. I'd recommend using a blowoff tube on your primary no matter which approach you choose. I keep a lot of headspace, but still always use a blowoff tube, because it's pretty ugly when it blows off and you don't have a tube.
The only time it is essential to go one way or another is when you are doing a secondary-- you want as little head space as possible there, because the head space is oxygen and your beer has already fermented, so you want to limit the exposure. In the primary, oxygen will get expunged when the fermentation's CO2 pushes it out. Your research has/will point out that a secondary isn't going to be necessary for your first time.