I would like to propose that two recipes be added for macerating compressed cobble (first stage only) into compressed gravel and into compressed sand. I've already gone ahead and written the code for my own instance which will be shared below. Values can be tweaked as needed, but I've tried to keep how long the process takes consistent with the fact that you're trying to break down 9 Cobblestone in one go but keep it open to lower voltage levels.

macerator.recipeBuilder().inputs(<extrautils2:compressedcobblestone>).outputs(<extrautils2:compressedgravel>).duration(135).EUt(10).buildAndRegister();

macerator.recipeBuilder().inputs(<extrautils2:compressedgravel>).outputs(<extrautils2:compressedsand>).duration(135).EUt(10).buildAndRegister();

Interesting, reminds me of the Sky Factory approach. Shouldn’t it be producing 9 normal items though for pushing into a packager for next stage?

I mean, it could. I didn't think that far ahead when I came up with the idea. It's a relatively simple change plus writing the recipes for the Packager itself. I'll write it up and submit a PR. If it gets in, great. If not, oh well. This was intended as a convenience addition anyways.