doubleriflejack

I found better shotguns then ones i was thinking of using for Double Rifle conversion. Merkel 12 gauge, JPSauer&sohn 12 gauge. Ellis used Simson 16 gauge and didnt like it. So naw, my choice's are 450-400 NE or 450-3.25"NE Winchester 405 included in this group. Dave Mason reamers are here for these 3 calibers. What do you think, which caliber, what Shotgun ?
All of you DR builders are welcome to suggest what you would build ?