Since Sky is a limiter, it's something I'd only use on the master. MotherComp however is different; it's a compressor.
Some plugins' parameters can make glitching and it's not necessarily due to the CPU usage. It depends on the code, what a knob or slider is really doing.
Code:
// Includes code from Tilt EQ by Liteon
I'm sure it's not just the Tilt EQ copied/pasted in there, but
tilt EQ is quite useful so you might be appreciating its effect irrespective of anything else the plugin is doing. In that case, just use the Tilt EQ in Reaper on those tracks and save Sky for the master.
Plugins like tilt EQ, presence EQ, graphic EQ etc. can be some of the most useful plugins despite how overlooked they are. It's good to have a toolbox with a lot of different and seemingly simple tools.
Speaking of adding pleasing high end (and having a toolbox of useful plugins), you'd probably like
Righteous4 by Airwindows. You have to learn how to use it first though (and the default settings are the worst possible ones).