I read your replies and I understand you are just suggesting an alternative and not saying that it's better than this or that. I like this video of Andreas Antonopoulos who explains why seed splitting is a bad idea: Bitcoin Q&A: Why is Seed Splitting a Bad Idea?

His exact words is that the suggested splitting method is absolutely not safe and that people should never make such custom shares and store them separately. He does go on to suggest that SSS is a better solution than custom-made splits because if you have less words than the needed quorum in SSS, its like you don't have any words at all. But having knowledge of 16 words like in your example makes it exponentially easier to bruteforce the remaining 7 or 8. 7 because the last word is a checksum, so it's easier to guess that one. Andreas also suggests that in the next decade, it should be possible to bruteforce 7-8 words with powerful-enough machines.