Alright, guys! You seem to know not much about saunas and their types...
And you've given a rather full, and interesting exposition on saunas. Thanks! I just stumbled back onto this thread while doing a search for something else.
I had a number of books on sauna. Doesn't make me an expert, naturally, but I was kinda into it that much when I lived in northern climes. Less interested living now in Florida, where everytime you get into your closed car it's a sauna.
As you say, people like different solutions and formulas, and their approach can be individually personal, or rigidly traditional. Here's mine:
In the US we usually have electrically-heated rocks in a wooden room. That in most saunas you can pour water onto. But not too often a cold plunge pool. And I usually have 3 goals, although not always all 3 in the same session.
One is to avoid muscle ache, after a physical workout. Can really help me. Another is to lose a deep chill, if I've been outside for too long with winter activities. The third is to prevent head & chest colds, or to mitigate those I might have already gotten. Although for a bad winter cold I might want a steam room instead, with some methol added to the steam.
I want a lower temperature, perhaps 175-180º F, so I can remain longer, get a good heat soak. Sorta like cooking food, the differences between quick searing and slow baking. I want the heat to reach deep inside my muscles, and to my joints.
But I still need some breaks. So I step outside, and lacking a cold plunge pool, I stand under a cold shower. BTW, I always prefer a men's-only sauna, so I can do all this unencumbered with any clothing. In some parts of Europe the identical routine is acceptable coed, but this is the prudish US.
My entire hot session lasts about 45 minutes. Then I have a long cold shower, and sit in the locker room for a while, still cooling down, or in a TV & reading lounge, if the facility has one for that purpose. Not only cooling, but also allowing my heart rate to decline, which takes longer as you age. Hence, I suppose, a source of clueless young guys bitching about the "old creepers" who don't instantly throw their clothes back on and quickly leave.
Serious sauna, however you perform it, should be a process and a ritual. It isn't the same as running under a shower, drying, dressing, and racing off in your car as quickly as you can. But if during your lunch hour you try to bite off more than you can chew in the gym, you're gonna be reserving just 5 minutes for a meaningless sauna cameo appearance. Then dressing like a quick-change performer, and wondering why some guys linger lazily behind. You've missed the entire benefit & beauty of sauna.