Rocketman must be away from his computer. I don't believe anyone has yet addressed the issue of moment of inertia (MOI). Don is the go-to guy in that area.
However, depending on the intended purpose of the gun--grouse hunting vs trap shooting, for example--it's very likely that you'll be looking for a different feel/balance/MOI. When Mickey Spillane came up with the title "My Gun Is Quick", he could have chosen it for grouse hunters. Not so much for trap shooters. At least some grouse hunters can make a muzzle-light gun work very much to their advantage. In some target games, muzzle-heavy may work better.
