Seiko DIY disassembly and reassembly tutorial: Chapter 3.
Pulling the watch mechanism apart is not difficult at all - especially if you handle the components with care. The most delicate of all is the balance wheel assembly which consists of 3 parts: the large and heavy balance cock, balance wheel and rather super delicate hair spring. This is the very heart of the watch - one slip of a screwdriver, sudden move or flip over and the heart is gone.
Yet if you watch the video you will see how it's done. And yes, this delicate operation can be performed successfully even by a hobbyist as long as the instructions are followed and the process is understood.
Again, there is a bit of a homework: sorting out and identifying the screws. There are 5 types of screws and while they are small, all of them are distinctively different. Easy.
Even if you are not a part of the Seiko DIY group, you should really watch this short video. Educational, fast paced and to the point.