Hi Fred, this looks like a lovely build, I've always really liked that red/white combination! As for the lozenge, it looks pretty good as it is, I'd probably just leave it if it were me :-)
I guess if you're really unhappy with it and have any spare lozenge left over you could always test out some variations by putting a coat of tinted clear over it. Problem is that it would also tint your rib tapes and edging. It's a great looking D.VII, whatever you decide.
Dutch