First, why cellar? Why not just buy and drink? If your hold time for most bottles is, save a handful, 12-18m then it seems like you are just managing purchasing convenience to align with consumption. If, instead, you want to build up a cellar for a purpose (you like your champagne bottle aged and you want to make sure the provenance is perfect or you buy to sell or you buy to bequeath or you buy because you just like to collect and that’s fun! Etc) then your approach to cellaring should align with that goal.
For me, the budget really matters as well as the rate of consumption. For example, if you said the budget is $10k start with $5k annual and the rate of consumption is 24 bottles a year I would do different things than if the budget was 10x and different things if the consumption rate were 3x.
In general, I don’t think people should plan to cellar unless they have a good reason and most people starting out don’t know what they will want to do until they are in it. Instead, I think more people should “paper cellar” (like paper trade) - write down what they would want to buy over the year and then see how much they deviate from it. Do that retro a few years and you will better understand why you are buying, why you buy what you buy, and why you consume what you consume. With this reflection, I believe you can better plan your budget and your buying, including whether cellaring is actually a good idea or not. [this is probably my biggest piece of advice]
Depends on how you plan to consume. I like older champagne and I value provenance. I buy older champagne from brokers / auction to scratch the itch now and buy new release to be able to consume in the future. It also matters where you are in your personal explore/exploit arc - I have a good sense of my preferences, so I tend to optimize for what I like.
Depends on preferences. For me, the early years are critical to start to get a handle on your preferences. To do that you need to sample a bunch of stuff. Auction is a great place to get older champagne (though, usually, only marquee champagne). If you want to cellar to drink older champagne, then retail is what lets you drink what you buy at auction today in 20 years.
Depends on your view on blends vs vintage champagne and how you consume. I would suggest a new person to champagne to buy and try the benchmark vintages over the last 30 years to get a sense of age and preferences. From there, buy what you like.
For all I said, I don’t recommend over thinking what is ultimately a very experiential process. It’s more about avoiding big mistakes vs doing something right. The big mistakes are probably over buying stuff you end up disliking and not experiencing a wide enough aperture of wines early on.
And, if you don’t read anything I wrote: buy mags.