OK....

Flat. No EQ at all at the mixer channel input, +3db at 180Hz on the Mastering Tools on the G70 (I like a bit extra presence for the bass).

No EQ on the graphic for the mixer power amp (Yamaha EMX 5000-12 2X500W). 2 JBL SR series 12" and a horn top cabs, Mackie 15" powered sub (just the one!) for the bottom.

I've never played an E60, but we did have some comparison Purgatory Creek files up at roland-arranger of the Natural and Classic pianos. Only thing I heard was that they were darker than my G70, not brighter..

What stage amp are you using? What PA system? What EQ settings are you currently using (including on board Mastering Tools - if the E60 has those)? Does the piano still sound too treble-y if you use good headphones or studio monitors (if you have them)?

Finally, the thing about an arranger is that it isn't JUST a piano. It's everything. So I'd be cautious about laying on a bunch of EQ to the whole thing, for the sake of a piano sound. I'd shoot for getting a good, well balanced sound on the whole arranger first, and then correct the piano EQ using the MFX insert EQ. And I would DEFINITELY use the Recorder to capture your playing, and listen to it out front to make sure that you aren't just getting a weird positional problem.

Final question... Do you turn off the internal speakers when you play out? Try it without them (put a dummy jack in the Headphone output) and see if that makes a difference. The G70 never had speakers, so that MIGHT account for some of the difference you are hearing (built-ins are often a bit shrill and treble-y, IMO)...

Hope this helps.