as for Roger Dubuis, the early pieces are still attainable at this point but the market is changing rapidly so who knows what it will be in the near future. All I know is that these early pieces are just stunning in terms of quality, uniqueness, and craftsmanship.
There is an amazing write-up and reference of Roger Dubuis and his early pieces by "A Collected Man." Don't know if I post a link but it is a great reference for his early pieces and should be THE reference since it has been compiled by several sources over the years ππ. It's a good way to learn about his early work and see what appeals to you π