YR.NO prediction at this stage is for rain, but that may change: http://www.yr.no/place/Ireland/Leins...w/forecast.pdf
Looking at the satellite version of the link that Fran posted, there appears to be some car parking spaces at the end of Castle Street, with access from there to the Castle, and that might be the best meeting place. I had suggested 9am in an earlier post but - unfortunately and much to my disappointment I am going to have to miss Saturday in spite of putting up the first post. I will send a few PMs to explain. I hope that you will go ahead with the meet up and have an enjoyable shoot; I will try and make Black Castle another day.