What could be the smallest longitude offset, I could have drawn on a map?

I would like to draw more than one icon on a building latlng. My icon is 8px. If I would like to draw a second icon on the same building, right next to the first, what could be the longitude offset?

Thanks.

For Css…
Your Icon is 8px. Then you set the margin by 3px. So you icon 6px apart.

For longitude offset…
i find this link

Hope it help.