Since we live in the same country, I can give you some advice, though I don't know whether you live up North or down South.. And no, this is NOT meant to sound like a guide to acquire drugs of any kind, just want to give a helping hand
For the question considering Psilocybe semilanceata (also known as liberty caps) , I would recommend you to wait maybe a month or two still. In the North (like Kuopio/Oulu and such) the season comes earlier, and the shrooms seem to be a bit more effective. Here South, the season is probably due October, if the warm weather seems to stay the way it is - unfortunately, the later the summer lasts, the more the season delays. I had a chat with a friend the other day, and he seemed quite confident though that September would be the perfect time to start!
If you've never found liberty caps, here's some advice. First of all; it takes time and patience, I would even say a meditative/spiritual state. Do not try to rush or force the gifts to be relieved too early, Mama Nature knows just when you should spot the first ones - and usually, once you spot one, there most definately is a bunch nearby!
Second of all; take time to scout the perfect place. Though once you know how to "think like a shroom" the places are pretty easy to find, but on the first try you'll probably be less lucky. Try to look for a damp place (usually you should try just after it has rained) on a meadow - birches and grass that grows on bunches (ruohotuppaat) are a good indicator of a spot. Our luckiest spots were on an old cow pasture and a sheep pasture.
I recommend to be very cautious with liberty caps, since shrooms always have something to tell. Sometimes they'll show you how beautiful the nature is, sometimes they just make you go all question marks, which doesn't necessarily help during a working. Though, if you just want to listen to what this piece of Nature has to offer and say, it requires a bit of courage and an open mind. A watcher, "tripsitter", is good to have around - someone from the "real world" you can rely on, and someone to remind you that everything is ok, at times of doubt. I once was the tripsitter for a friend on shrooms for the first time, and she acted like I was the Great Wise One - or her mother. "Can I sit down now? Can I use the toilet? Hahahah I wanna laugh - is it ok if I laugh? Hey why do I feel this weird? Is it ok if I feel this way? Hey wtf am I doing?" And I of course answered all her questions - to her, they were very important and valid.
I wouldn't recommend trying to get ayahuasca in Finland. There are some people who do it, but since they are not shamans, I do not trust what they do - of course, if you would brew it yourself, it would be a whole different thing, yet I feel that for the trip to be "perfect", there'd still need to be that one shaman taking it further and further.
I'm from Espoo, so I guess I'll still have to wait a while! :/ but oh we'll, more time to think.
And yeah, I'm not jumping into anything, going to really think about this. I wan to try it though. Part of my heritage is shamanism, and I would like to delve deeper into that.
Go I hate typing on the phone..