For vertical vessels I suggest to add a field to add a material for lugs on top o f the vessel and also another field to selected the material for lugs on bottom skirt (tailing lug).

It is very common to have columns in for exempla stainless steel that the sot lugs should be also in stainless steel, but for economic reasons the skirt should be in carbon steel. By this way the tailing lug should be in carbon steel.