I would argue that if you reach the same intensity with two different medias then you have provided the same peening results to the almen strip. Saturation and therefore intensity by definition would show that if you gained full coverage on that almen strip then the arc height would be the same (within a reasonable tolerance) for both medias. The almen strip being in the same condition would support the argument for same peening benefit. There have been articles published in the shotpeener with data and analysis to support this.
Fortunately for me, all of my customers generally require that surface finish be controlled prior to shotpeen only. It is possible also that if you are peening at such an intensity that surface finish is a concern, then you also have rollover or dimensional concerns, and may need to polish either way. We frequently have to polish or hone surfaces and holes after shotpeen to meet final dimensions, within stock removal allowances. There is data to support light polishing actually providing positive benefits to the shotpeened surface.
