That what the version byte is for. The first letter of the address is what keeps you from sending currency to the wrong type of address. All changing the base58 does is make it more error prone. If I had not happened to stumble upon the fact that GRS uses a different hash algorithm for addresses, I may have implemented GRS to some application using sha256, which would have resulted in me and anyone using that app to lose money by sending to an invalid address. Is very unusual for an altcoin to change the address hash, in fact GRS is the first I've come upon.

I see the bip32utils project you have forked already includes a base58 implementation using groestl. Could you put it up on pypi so I can add it to my project? My project is called moneywagon, it's a cryptocurrency platform for building wallets and exchanges and stuff like that on top of. Also, it seems you also removed sha256 from the transaction serialization code too? If so then another forked python library with groetsl support is needed to make transactions, so the groestl-hash function needs to be added to pypi too.

Also I noticed there is a groestl fork of bitpay insight on the groestlcoin github. Is there a pubic instance of this running?