Your advice seems sound for very mountainous terrain ( in terms of adding / removing clothing ) ..however in the UK we would be adding/ removing layers every 10 mins ..as it's more " undulating " ..not just one big up & down ..Merino wool base layer is amazing. As well as being super warm, it breathes and one can wear it for days without it getting smelly. Thr mistake most people make is wearing bulky layers on top and not wearing enough on the legs. The combined surface area of ones legs is more than the trunk but because legs don’t really feel cold one doesn’t realise how much heat is being lost. Fleece trousers can make an enormous difference. As the body cools it cuts off circulation to the less important bits but freezing hands and feet are miserable and not great for bike control. So, by keepimg the body slightly warmer than comfortable there is a much better chance of extremities staying warm. Having said this, Heated socks are great. I bought LENZ ones for skiing but have used them for sub-zero mountain biking. Heated gloves are great too. Motorbike ones are waterproof as well. I use some £15 Chinese ones For short rides but really good ones a worthwhile investment. If it is dry, one cannot beat down vests and jackets. Not only warm but breathe and dont restrict movement. If it’s wet one needs a breathable shell. Goretex is the best but other membranes are nearly as good and cheaper and sometimes more robust. Remember that non of these breathables work once the DWR coating wears or is washed off as water no longer beads off and the soaked material can no longer let water vapour through. I have one jacket for dryish to showery conditions and goretex stuff to only be worn when it’s really bad , Biking involves getting pretty hot going up and with windchill a huge temperature difference going downhill so clothing needs to ventilate. If the weather is bad, it’s a nonsense taking a waterproof jacket off to remove or add clothing - everything gets wet. Better to add jackets. So, base layer, mid layer, light waterproof jacket for up. Add down jacket or vest or both plus second waterproof jacket for down. Remove two top layers for up.