Street Parking Regulations for a Home Wedding

The subdivision's streets are not very wide and none of our neighbors park in the street on a regular basis(everyone parks in their driveway).

When people do park in the street, half of their vehicle is covering the (someone's) grass or else cars can't get through the street, comfortably.

We are friendly with all of our neighbors and all are invited to the wedding.

If everyone accepts the invitation, we'd expect 18-20 vehicles needing to park.

How should we handle this? We live near a cul de sac and there are signs around it saying 'no parking.'

Should we ask the neighbor across the street if we can park cars on his property? Or is that asking too much? Our lot is too small for this.

Or, should we just downsize our guest list?

p.s. We can fit 4 vehicles in our driveway... but we're saving those spots for the elderly/handicapped/grandparents.

Other suggestions are welcome.

*Already contacted the city twice to ask if we can have people park in the street on one side... its been weeks... no response.