Hi Geroli, that wood work looks beautiful, and will make a great back drop for the brass and steel of the engine. Don't be intimidated by the soldering, but do a bit of reading up on it, get or borrow a good torch, and then jump in with both feet. In the end you will get a good piece to finish up, or you will get a piece of scrap and a bit of "earned" education, and you will know more about soldering and what not to do, than you started with. The single most important issue is always cleanliness of the metal surfaces, and good flux, to keep them clean as they get hot. If you're soft soldering, any zinc chloride based flux will work well for you, and it will work well if you are using any of the "soft" silver based solders. For hard silver, use borax or a borax based flux, such as is cheap and easy to come by for brazing. It everything is where it needs to be when it is done, and if gravity is your friend, and holding things in place, the hardest part is the patience to let the biggest lump of metal get hot enough, and that can be gauged by just touching it with the solder while the flame is directed elsewhere. The solder will slide easily across the smooth metal until it gets close to temperature, and then it will want to stick a little bit, this is just moments before you are ready to solder, so at that point, make sure you've got flux on, the parts are in place, keep the heat on, and when the solder flows like water, it will wick into every opening and crevice. Then just take away the heat, admire all sides, ensure you've got good fillets between pieces, as that indicates good solder adhesion, and once it is certainly solid, dump it in water, both to cool it, and to start the flux removal part.
What ever you do, don't let an error dismay you or make you question your ability, no one that works wood that well can't solder, and you will be very happy when it turns out well, and can be machined to go on with the build. With that holiday behind you, everything should make you happy and this build should be just a few solder joints away.

Cheers, Jack