This error didn't matter (at all?) with the initial SGA catalog because they Hyperleda diameters tend to be much smaller than the D(26) diameters we have in-hand now. What happens is that in a galaxy group with a large central galaxy and a smaller companion on the periphery missing this factor of 2 can exclude the satellite.
I think I'm missing a factor of 2 in this part of the group-catalog generating code-- https://github.com/moustakas/SGA/blob/main/bin/SGA-build-parent#L3744
This error didn't matter (at all?) with the initial SGA catalog because they Hyperleda diameters tend to be much smaller than the D(26) diameters we have in-hand now. What happens is that in a galaxy group with a large central galaxy and a smaller companion on the periphery missing this factor of 2 can exclude the satellite.