Usually during good tropo conditions, antenna aim won't matter too much for the Rochester stations as they bounce off Lake Ontario.
A 4 bay antenna such as the 4221 has a fairly wide beam-width as well which also helps in this case. WROC and WXXI are usually the first 2 Rochester stations to come in during tropo conditions as they are on fairly clean channels, especially WROC on RF 45. WXXI on RF 16 is a bit harder to receive though due to CHCH now using RF 15.