Hi Bernie,I am so happy to hear about your positive impressions on the Ketron Event X. The Real Styles sets a new benchmark on the level of realism that can be attained by an Arranger Keyboard.
Ketron makes it super easy to interface the Event X with any other keyboard. Basically all you need is to allocate 2 common MIDI channels between the two devices to marry them up.
For instance, you could allocate MIDI channel 1 for the RIGHT1 part while allocating MIDI channel 2 for the LEFT which would control the Styles.
This lets you treat one device as the master while the 2nd device becomes a sound module.
What you have done is perfectly alright too. In your setup you are free to play on both the Event X and SX900. You can control the volumes independently on both keyboards by adjusting the physical sliders. You can play a style on either keyboard. This is the perfect setup to enjoy a free jamming session.
AJ has posted 105 Tutorial Videos and Product Demos on his YouTube Channel:
https://www.youtube.com/playlist?list=PL8Ya6B_eNDemvAD7I3WYwqIBg5mMHCe2lWatching his videos is the fastest way to master the Ketron EVENT. He covers every single detail. I was astonished to find the level of control and unique feature set of the EVENT platform.