Hi Chris!
My, what exciting news, and all congratulations your way on the Thorn-to-be! The Club Tour is a lovely bike indeed. You'll do just fine with the parts swap and build and if you run into any snags, the Forum membership will be happy to weigh in with help as needed.
I'd be grateful to hear any opinions regarding the above order, or put me right if I've made some obvious mistakes (more than likely).
Aw, Chris, I don't think there's any one right or wrong way to go about it, but I'm happy to share the approach that works nicely for me...
To save time and reduce errors, I tend to make my frame-up builds based on dependencies, which I see you (and John; hi!) have taken into consideration. In other words, I start at the base and try to to things
once so I don't have to remove components to redo something.
Accordingly, yes, a frame-sealing and painting the BB face is an excellent starting point, both best done with no other parts installed and with the frame free so the goo can be encouraged to run into the deepest recesses. Do be aware, if you use a square-taper BB with internal rings, facing is unnecessary, and if you use any BB with an outside mating surface, the fresh paint will soon be scraped away. I paint the exposed faces anyway *and* treat the threads/interface with grease or anti-seize.
I bolt on the saddle, then insert the well-greased seatpost into a well-greased seat tube to a point *just below* the minimum-insertion mark to prevent scarring of the 'post finish. Sometimes a little scuffing can occur or an unseen burr can make an unsightly scar and you want to catch that before you adjust the 'post to riding height. Mars will show later if they're above your usual riding height.
I grease/anti-seize, or LocTite as I go and use a torque wrench on all fittings. I refer to a list of torque readings so I don't have to look them up piecemeal. Wheels are pre-built (fully tensioned and trued) and all components (even new) are pre-greased and pre-adjusted before installation -- it always amazes me how many components are sold "dry" except for the thinnest skim of grease to prevent corrosion in shipping. Not a recipe for long bearing life if bolted on directly.
Next step is to insert the wheels with tubes/tires and cassette mounted so they can support the bike if necessary and they are required to set brake pads and drivetrain. By the way, brake pad setup goes so much more quickly if you disengage the return springs first. V-brakes invariably need their spring tension equalized before setup.
I then bolt-on the brakes and set them up, then the crankset with pedals, derailleurs, and chain. Pausing here, I do my baseline drivetrain adjustments: Derailleur throw stops, B-stop position, chain length, etc. entirely cable-free. Same for the brake and pad setup. Later, it is just a matter of running the cables/housings and doing the indexed setup/tension adjustments.
Moving forward, I install the stem with a full stack of spacers, bolt on the handlebars, and set my brake levers lightly to position (I usually prefer my drop 'bars level on top and about as high as my saddle-top. Brake lever placement depends on 'bar drop and reach and the clamp positions are marked with masking tape so I can reset them quickly after cabling). Shifters go on at this stage, whether they be downtube, bar-end, or brifter.
At this point the bike is pretty much assembled and ready to remove from the stand to set the hard points (seatpost height, fore-aft saddle placement, handlebar height/reach, brake lever placement) to my preference. I always get on the bike at this point to see if it indeed feels right. Once those hard-points are set, I know how long I need my cable housings, so I cut those and cable up the brakes and mechs, setting the tension as necessary.
Mudguards next. Even though it means removing the wheels, everything else is adjusted more easily without them, and having the bike otherwise complete makes a test ride possible and it also makes it easy to arc the 'guards to the inflated tires (extra steps required if you have a bike with ramped dropouts). Mudguards require I take special care, 'cos I fit them with long mudflaps and use a meter-stick to measure the angle between flap-bottom and tire contact patch to ensure the chainrings are shielded from direct spray. I'd love to do without the flaps, but they're necessary for my conditions and easily double the effectiveness of the 'guards for me.
Once the mudguards are in place, it is time for the racks. If the racks are adjustable, I make sure the top surfaces are level and placed so the load is carried as low and close to the center of the bike as possible. Occasionally, I will deliberately tilt a rack to a small degree so bags will slide firmly to one end or the other to prevent shifting; it depends on the combination of bag/rack used.
I install 'bar tape as the last step in case I need to adjust the brake levers or need to adjust cable housing length. a final cleanup of any exposed grease or fingerprints and the build is done with little if any need for further adjustment.
Lights -- particularly wired dyno lights -- disrupt the process a bit but are typically added to a full build, even though it may mean removing the wheels and possibly the (fitted) mudguards once again. Everything else has to work first before the lights go on.
'Works for me and gets the bike done and me on the road soonest -- always a priority with any new bike!
Best,
Dan.