One more: https://www.reddit.com/r/languagelearni ... resources/
Thanks for all these, Reineke!
Based on all this, I think my strategy is pretty clear. On the Cervantes website test, I got level C1.4, which means C1 should be the appropriate exam level, even though it will require a lot of work.
I will work on my general Spanish skills till April or so. That means courses, lots of grammar work, vocab, all that. Writing and speaking too, when possible, but I need to get all the gaps in my knowledge filled, before I build on that. Input: yes, sure, but it cannot take majority of my Spanish learning time by far.
In April, I will get the preparatory books. I will buy one (probably Cronometro), and borrow others from the Cervantes library in Prague. And I'll do all the preparatory writing tasks and speaking assignments I can find, and I'll work on improving those skills. I should be ready by November. July would be better (as that would mean I could have more time to fully focus on German), but I cannot fully prepare with all the university exams going on till the end of June.
I highly doubt I'll pay any teacher. Sure, one or two hours of speaking on italki may be useful before the exam. But I don't know. It is not just the issue of my overall distrust towards teachers and lots of experience with them. And this time, the available books should suffice, as the Spaniards are not as formal writing crazy as the French
Money is the issue too. My "spare" money is going to be spent mostly on my education during the next year or so. I'll need to buy quite a lot of resources to prepare for the French medicine exam (I really wish I had studied the whole degree here), the DELE and the Goethe exam are not that cheap either (and don't forget about coffee). Buying high quality courses and preparatory books is a good investment, as I'll be using them a lot, I'll need to make notes in them, I want the up to date editions. The library books are a bit limiting, but will still be needed as I can't buy everything. I can look at a book, leaf through it, read recommendations, and I'll know whether it is worth my money or not. But a teacher is a highly risky investment and I cannot afford to waste hundreds of euros.
I believe I am totally capable of preparing myself to pass the exam, if only I put the time into it. I do not expect myself to pass with extremelly awesome notes, I don't need those. Perfectionism is needed elsewhere now.