Connor I had already looked at that source but never paid attention to the >=32 check. That gave me new hopes but things still fail even when I set m_iStyle to 32 and try with and without dispatching a pattern value. The Dispatch functions are working and I can successfully set these values before entity spawn. Nonetheless, the lights still flicker.
Also I really don't understand what you mean when you say create everything in plugin_precache.