Oil + additive viscosity

I have no idea how to compute that. My issue would be that the oil stabilizer would ruin the synthetic's more consistent viscosity properties, and perhaps most or all of the positive qualities of a synthetic. And not to mention what might be the result when the 2 additive packages were mixed....

Any point in doing this? Need/want a higher viscosity synthetic, or more ZDDP from an SN rated synthetic?