Thanks to these two helpful articles:
https://en.bitcoin.it/wiki/Technical_background_of_Bitcoin_addresseshttps://en.bitcoin.it/wiki/ECDSAI have determined that my public keys are compressed, and that uncompressed keys starting with 0x04 are a thing of the past.
These are my next possible steps:
1. Determine how to decompress my public keys and continue which what I was doing before using the decompressed keys.
2. Extract all possible 32 byte private keys and generate public keys and hashes of those public keys until one of these hashes matches the hash for my address.
It occurs to me that if the runtime for going from 32 byte private key to hash of public address is small, as long as someone has the correct address, they should be able to essentially brute force an entire hard drive to find the private key that is associated with the address. That would be a cool recovery tool to have, it would be slow but sure to work. Also if the runtime is too long, you could start with byte sequences that have higher entropy, because byte sequences with low entropy are unlikely to be private keys.
Any recommendations are appreciated.