Tumbler questions

Hi guys,

After seeing JOGARA's thread about his new tumbler (thanks for sharing), I was thinking of picking one up myself. I will be using it to deburr/polish mostly flat aluminium parts and plan on going for the plastic pyramids followed by impregnated wallnut media from Moleroda.

Two things I am a bit unsure about and wanted to check over are - would the green pyramids be enough to break past the aluminium oxide layer (on the plate surface when you first get it from the supplier)? Also, would tumbling with this media be suitable for fine engraved parts (0.3-0.5mm engraving depths)? Cheers.