Ceremony chair rows

I think it really depends on what you want it to look like. If you want full rows of chairs, you can tape the extras off and remove it for pictures. If you don't want empty chairs, only put the number you need. Maybe you could make some diagrams to help decide the look you want?

I think you should put a small sign on either end of the rows you need reserved. Maybe just a tented card that says reserved in pretty writing. This way you don’t have to worry at all.

I would direct your family to their preferred seat the day of the ceremony rehearsal so they know how to walk in, what order they’re walking in and where they are sitting. Or give them a diagram so they know where they are expected to sit

As far as unused seats... maybe you can do something like this. It can also be curved instead of straight.

I know there will be only 2 seated in the first row on one side but it can look more symmetrical this way?

The front pews on either side of our church are shorter than the ones behind them. As long as you line them where there's a chair right along the aisle like in Bird's diagram it looks totally fine!