The lottery, as i understand, is only if they are double booked for that day, otherwise the date is yours. It is so everyone has fair game at that day. They will continue to take other people into consideration for your date and time until your contract is signed and in their hands (which I understand you cant do that until 8mos out).
For an intimate wedding though, I would literally take it as written in stone. The only minor change that probobly would be made is if someone else also wanted that time, you might have to go up down two hours (not a huge deal).

But I wouldnt worry about it very much. I scheduled my November wedding in June (6mos out) and had no problem getting the date and time I wanted) ...
If there is a problem and your WC tells you that there is a spot but there might not be enough people to help accomodate your event (which they told me at one of the dates I chose)... I immediately switched dates because ITS MY WEDDING

I want all the service I pay for
GL! And dont worry