@SeedSigner has a way to let you do it…putting first 11 or 23 words, then select remaining random bits and valid check sums supplied for that bit set. I can show you screenshots in a few mins if you want.
I think the issue is with one of the prior words though. The checksum is a word with not a lot of similar options.
The checksum is the last 4 bits of the first 23.5 words. You out in 23 words and then manually put in 0000, 0001, 0010, etc for all 16 combinations
Turns out it’s just 3 bits of extra randomness, so only 8 combinations to try. Are you working on a 12 or 24 word seed? https://image.nostr.build/f0802feffe351c3e3252173496542f3695959a9241c1868d0b7480bade917273.jpg https://image.nostr.build/ae9748e8a6cfdc1ff2ad35024870a905bf22c550e915cc02e24095a2b1827b8f.jpg https://image.nostr.build/c09c7a074334fc0308efad2129e15cba98e6cf0c3aba9aa049576d1dc1cda5be.jpg https://image.nostr.build/a393d7230a91cb82c38eb4fcad440fe31cc99e58af296038ed677e10b4369dff.jpg
This @SeedSigner feature lets you use the words themselves as entropy source. A big bottle of 1024 double sided seed word orange pills. https://image.nostr.build/6775e652602d110ed805f6c6328eb9a41174c7af2ecf78e60dca8ce885e4b503.jpg