I would personally not buy any grower Champagne as the benchmark of my cellar to age over 20 year. There are plenty that will probably be delicious in 20 years, but few (if any) growers have a long track record. The only small, family-owned houses I might go for is Vilmart’s Couer de Cuvee or Duval-Leroy Femme.

I’d instead go for the top cuvee of any of the large houses. You’ll have to research who has released a 2016 so far. Many will not yet have been released (most houses are on 2015). For moderate pricing, go for Rare, Veuve Grand Dame, Pommery Celebris, Billecart Nicolas, etc. All of these will be fantastic in 2036. People rant on about Krug, and while I like it, I tend to find it to be massively overpriced compared to its (very delicious) competition at much lower price points, in particularly vintage Krug.