On the solo pool, do you have a set starting difficulty (diff_xxxx) setting you put in the password, or since you specify works with nicehash and miningrigrentals, are those ports for equihash high difficulty ports?
I looked on your start up help for miningrigrentals but didnt see anything there. You might have it specified somewhere else, I just couldnt find it.
Thanks for the question. Share difficulty is same for Nicehash and standard rigs. However, the Nicehash port is 100% compatible with Nicehash stratum.