Hi Ed! I hope everything's ok
I just wanted to say that I haven't started the buildup. I've mostly done easy 40min runs 2-3 times/week + some strength training.
I plan to start the buildup in January and do it for at least 6 weeks. The reason behind this is that in January the temp will probably be around -10 deg C and I won't be able to do fast sessions. Easy running will be ok. So by the middle-to-end of February hopefully I'll be able to start on the cycles.
Unfortunately I still have an issue with my easy run pulse/pace combo... I struggle to not let my pulse go above 151bpm while easy running(133->151 is my aerobic zone interval).
I'll do a 'test' next week where I'll aim for a pace of 5.30/km for a 30-40min run and see where my HR's at. My 10k pace should is around 4.15-4.20/km so 1min slower as per your HR training article.