You can work with the measurements you like and your selected caliber and confer with the barrel maker -- he will not let you make one too thin for his own sake. Dennis is correct, however, that many southern barrels, lacking a drastic swamp, will be much heavier than we expect these days, so factor that in with some creative calculations. Making it in .54 will probably help some, but I would still guess a typical southern tapered and flared barrel to be roughly 2x the weight of the Rice Southern Classic.