BG225733103 RTC? Wich definition of RTC are you talking about? Your Question makes no sense...There are lots of different meanings for RTC. See here: en.wikipedia.org | wiki | RTC If you want people to help you stop using acronyms and give more context instead of just a short question.

BG225733103 T12 soldering tips are all equal in diameter and the position of the contacts is also the same - so any tip fits in any handle. You select the tip type via the menu of the soldering station, so the temperature regulation can adjust according to the thermal mass of the tip used.The difference between the handles is just for personal preference. Some people want the classic blue plastic with the thick yellow silicon sleeve (k10 type), others prefer the lighter slim handles (type 4, 5 and 6) or other colors (types 1 and 2). The (separately available) alumin(i)um handles look nicer and are even lighter, but get warmer than the plastic handles when used for a long time. The carbon fiber wrapping on those used instead of the silicone sleeve doesn't help either to keep your fingers cool. There is also a stainless steel handle which is a little bit shorter than the rest of handles, so the tip sticks out further. But my guess would be that this also gets quite warm.

BG225733103 Sure looks like a scalpell blade to me. The blade shown here seems to be for use with a scalpell handle no 3 or 4. Blade shape could be a Rüttgers no 11 or an Aesculap no 25. But the mounting slot is the same for all blade shapes, so you can use any shape you like. Use your favorite image search engine to search for "scalpell blade shapes" to find the one you want.

BG225733103 Bare wire is probably best. I suspect that it was never intended for banana plugs, but as pure screw terminals. Hole diameter in the plastic head is about 5.5mm.

BG225733103 I suspect that the fuses that are currently present will be installed with respect to the current. My board contained 5A fuses.

BG225733103 On the board is no circuitry that would prevent you from using the +12V with the -12V instead of GND - the screw terminals are connected straight to the ATX connector via a fuse only. So yes, you __could__ get a 24V potential. If it works or if it goes bang depends entirely on the ATX PSU that you connect to the board.

BG225733103 all Ω values are listed in the overview.

BG225733103 1kΩ is listed in the value list shown in the overview, so yes there are 20 pieces.