I bought some HM oil for my 93 Aerostar. As of yet I haven't used it, I might mix it 50/50 during my next OCI, and see if I can lower the oil consumption a little more. I actually changed from 5W30 to 5W20 and reduced consumption , I thought it would go up, or stay the same. When chatting with a friend he sent me something from Shell oil company that helped explain why that might have happened. Since joining BITOG I like to experiment a little.
According to Shell's study: "Lower viscosity lubricants give thicker top oil ring films", according to a chart in this study. Exact reason why I don't know, perhaps someone else who understands this better can chime in. This I believe can actually reduce oil consumption in some cases, if the consumption is caused by the rings. Guides are another story I would think.
JMO based on what I've read and am in the process of digesting. They used 5W40 15W40 and 5W20 for the study.