i think you're probably going about it the right way with the big sheets.
however, i ordered bamboo worktops cut to size from https://www.worktop-express.co.uk/online-bespoke-worktop-tool/ and they all fit together and were installed without any drama (i think i had to plane a little bit off one of the back edges)
any minor gaps on the back edge close to the walls were covered up when i did the backsplash tiling.
i think you're probably going about it the right way with the big sheets.
however, i ordered bamboo worktops cut to size from https://www.worktop-express.co.uk/online-bespoke-worktop-tool/ and they all fit together and were installed without any drama (i think i had to plane a little bit off one of the back edges)
any minor gaps on the back edge close to the walls were covered up when i did the backsplash tiling.