I run my bodies on the rear mount in the lower position, most run it on the higher position which I believe will raise the body by 10mm. Then for shure the glowplug is placed below the body line.

About rough surfaces making vortexes slownig down air you are probably right bur fast flowing air will bring more fresh cool air. Also rough survaces wil hold dirt much easy blocking a heat transfer to the airflow. And yes, a normal start of anodizing is an acid bath to clean the surface, when doing at home we use car battery acid from the car parts shop.

I am busy making a vibrating machine with stones or I will get cracked nut shells to polish the parts I make.