Larry,

as regards factory styles not being fully filled, as you may know with all Korg models you can actually also access the factory preset areas both sounds and styles and add or eliminate styles in the factory presets. ( somehwere in Global, factory styles protection: off. You can then load either individual styles or a complete bank of styles into the areas that you cannot reach now.
And if you download the (free) Dopamine set (from a guy in Frane) you will have ample stuff to fill up with. Note that he states that his set obviously has been programmed for PA900 and PA600, but this should not keep you from loading individual styles and/or sounds.:
https://dopamine4korg.wordpress.com/

By the bye, a very brave move from you if you are used to Yamaha And once again you prove my point ( often expressed) that nothing beats the combination of two different brands, be it MOTL or TOTL arrangers.
Looking forward to your further assessment. How is the amplificaiton by the way ?

regards
John

P.S. a glut on reverb settings has always been the problem of most arranger keyboards and certain Korg. Generallly they have set the reverb levels to 50% ( 64 out of 128) which is way too much of course. You will find that with adjusting these significnantly and with properly adjusting the overal EQ in the global mode it will already sound much and much better !!!!