You shouldnt be building lights for dynamic lighting. Enable Force NoPrecomputed Lighting in World Settings and then Build once to get rid of static lighting. Now you can start playing around with your movable light sources. Also keep in mind that you can use reflection capture actors with dynamic lighting, which helps blocking skylight reflections for interiors.
There are a couple of dynamic lighting solutions with GI(LPV, HeightfieldGI, VXGI, DFGI) but i really doubt any of them will give you the quality you would have with Lightmass