The author of the famous Ultimate Megademo, released in 1992, answered my questions regarding his past work. As a reminder, he is the one who started everything regarding realtime 3D usage in Amstrad CPC demos. He is also one of the first guys, still in a demoscene context, considering usage of a secondary machine to enhance his productivity. Enjoy reading the interview here (also added in Articles section). Thank you Andreas for your time !