for RealisticPower mod users: Try using the Clockwork mod also, in order to gain the ability to control not only the day/night length, but also the ratios of day/night/twilight. To make Clockwork's settings take effect properly, set RealisticPower's day length modifier to 1. Also, a new game begins at day-cycle time 0.50 exactly.

For Kenira: Please consider offering support for Clockwork mod. It seems to work fine alongside RealisticPower but it took some research to find the right settings to do it, and I could easily be missing something, so I can't say for certain everything works properly.

I might take a look at it, but no promises

Thank you. That much is all I ask.

A bit late but there you go. XD
Sadly there is no way to force a multiplier on Clockwork, but this mod now respects the settings of Clockwork at least (you still have to set the Capacity and Daylength settings for Clockwork to 205 for 24h days)