+1 for eagle's sentiments on the ivory grips. It's preference on either one.... And I own and like the two piece, but the 2 piece is the suit and tie and the 1 piece is the tuxedo ... Strictly my opinion there. I do believe also that the 1 piece will sell faster as well.
Any time you have to poke a hole in Ivory you do it disservice. Holes can lead to cracks over time. Properly shaped and sealed Ivory will retain its finished form for long periods of time ( years ). Witness the historical Ivory from Colt in its early years. Those firearms held in collections are still beautiful. It is only a personal preference, but I reason a good one. I completed, some years ago, a set of Colt and Winchester rifle, both stocked in Ivory. Both still are perfect and undamaged, because I sealed them correctly at the start. Q