If weight is a consideration, don't you add poundage with a full tang? Can you oxidize the edges of the tang to keep it dhu? Could you skeletonize the tang and still consider it "full"? Compare the skeletonized buttplates on some shotguns or drilled out ultra light bicycle components... The difference would be that all of that missing metal would be sandwiched between your scales, which might then have to have a different means of attachment. Your pictures will eliminate my next thousands of words...
Cordially
MacLL