Whole day or 4 hours for microwedding?

Hello all I am getting married on July 11 2020. My guest list is extremely small less than 20 guests. However I like the big wedding feel. We already have a photographer and videographer paid for. The venue I am using is a fire hall that is very elegant for weddings. I do not have any bridesmaids, maid of honor, groomsmen, or parents (deceased on both sides). With that being said the venue charges for a Saturday $900 for full day or $500 for 4 hours . You also get 2 hour setup time separate from your event time included in each price. Usually they double book Saturdays so if I wanted to guarantee NO ONE would book Saturday I would have to pay $900. I was gonna do that but because of the size of my event it would not make sense. I made my own centerpieces (4). I don't have alot of decorations but I already purchased (chair covers, sashes, linens already) think it would be best to do the $500 for 4 hours. It takes the DJ one hour to setup the caterer would setup at that time as well and I have an additional hour to do my ceremony and then the actual reception following right after. So with that small amount of people it would not take 2 hours to decorate 4 tables and a sweetheart table. I've discussed with the FH and I am seeking more feedback.