The trouble with all the conversions, mine included as I see them cosmetically, is the transition from the old tube/monoblock and the new barrels in terms of profile. and the fact that shotgun tubes are effectivly curved.
I don't think that I can comment from measurments alone, it is so subjective. To make it look really good then you have to strike up the barrels by hand to get smooth transitions rather than a collection of tapers. You can see it on mine in certain lights and I will restrike it when I have time (HoHo).
I would I think have the transitions made abrupt without taper and strike by hand to blend them in.

Regards