As you may all know the "Lady Grey" is recorded as arriving at Pictou on 16th July but I have recently found a family in Cromarty for the 1841 census (6-7 June) who went to Pictou on the aforesaid "Lady Grey" (Donald and Jane McKenzie). This means they must have made the crossing in under 40 days. I guess this means a reasonably quick voyage by the standards of the day, although it still didn't prevent the outbreak of Typhus.
Anyway thought I would just post this as it may be of relevance to other researchers. On the other hand everybody else might have figured this out before me - not always the sharpest tool in the box!