The G70 is a nice instrument...unfortunately it is too heavy for most OMB players.
Keep your G70, Cassp...you really like the instrument, I can tell, but consider that none of us are getting any younger, and that big old G70 isn't going to get any lighter.
Save up and get a lighter arranger for your NH gigs...an S900, as you suggested, or, an E-50, if you want to stay with Roland's OS, and keep the G70...if you sell it, you may never get another in the excellent condition yours is in.
Ian