LOL! I don't know about "guru", but if you rebuild them enough times it gets easier. I have had to rebuild the carbs on my long term regular ride (also 78 CB 750K) probably five or six times over the last 29 years (holy crap, have I had this thing that long?), usually as a result of inactivity (letting it sit). I still hate messing with the carbs, but I have gotten better at making them work right.
As for the rust on the shaft in the first pict, you can either completely disassemble everything from the shaft(s) and have them replated (ACK!), or just take some steel wool to the rusted areas and oil lightly upon reassembly (best bang for the buck). You can slow the return of the oxidation by storing the bike indoors, as opposed to parking it under a tree like so many P.O.'s (previous owners) are known to do.
As for the ports in the last pict, I usually give the carb body a good soak, followed by aerosol carb cleaner through the ports, and follow that up with compressed air. For soaking I have grown partial to my small ultrasonic cleaner with straight simple green. Just don't soak then in simple green for too many cycles or it will start to turn the aluminum black. For any remaining stubborn deposits they can usually be targeted with lacquer thinner, just avoid the rubber bits if this step is required.
Make sure to check that the accelerator pump nozzles are free and clear. Also keep in mind that the rubber tubes connecting the accelerator pump circuits between the carbs have a brass restrictor inside, so if you replace the short pieces of rubber hose, don't forget to salvage these restrictors.
