Sine.Spaces uses Deferred rendering. So you can use as many lights as you wish.
Below is the Unity5 documentation for scene lighting. It's a bit long but worth the read.
Here is a video on the basics of light.
Baking your lighting will help with overall performance.
1. Make sure any objects that are not moving are set to static, you will find the tickbox upper right
corner of the inspector when you select an object.
2. If the object moves in any way leave it unchecked.
3. Go to Window > Lighting
Be sure the following are checked:
Precomputed Realtime GI
Baked GI Setting
Select the Baked option under Ambient GI drop-down box.
Set your Baked Resolution between 8 - 15, the larger the scene the lower the number here.
To have lights show on moving objects and avatars you will need to use Light Probes.
1. Create and empty game objects.
2. Add the Probe Drop Plane component.
3. Move this grid with globes to the top of your scene, the object is to scale it so it covers
the overall area of your scene. So over buildings, larger objects.
4. Adjust the Density Setting in the Drop Plane so the globes are evenly covering your scene.
If its darker add a bit more then if a scene is well lit.
5. Click Update and the drop plane will expand.
Note: If you have additional dark corners, you may wish to add more manually
using an empty game object attach the component Light Probe Group moving one probe into
the dark area and one nearby in the lit area to reflect off each other.
When you have everything set up click 'Build' this can take quite awhile a suggestion is run it overnight.