For layering stuff theres pretty more you can do apart of using EQ, try linking al the layers to different mixer tracks and applying different EQ's but kepping one of the synths as the main one (making a little boost in the high mids section while applying a sublte cut in that section on the other synths), then you can link all the track to a bus and apply some multiband compression (Maximus it's great for this if you are using FL) and some reverb/delay (or both). That should make al the synths mix together making them sound like only one. You can also eliminate all the Reverb and Delay on the synths and only use the one in the final bus to make them feel like they are only one synth.
(Sry for my bad english) Good luck with your productions man!