Hard Anodize on Anodize Abrasion

My company is in the process of developing a fully machined assembly which includes a piston in a bore which are both 6061-T6. The bore has a low friction seal in it and we hard anodize and polish the piston to give the seal a good surface finish to mate against. We ran an endurance test for 15,000 cycles to test the hard anodized piston finish and it held up very well. There was some slight scuffing where the piston rubbed on the wall of the bore, but nothing significant. We ran the test with the bore being the machined aluminum with no finish. We now need to coat the bore for coronation protection and I need some suggestions. What is a good coating for the bore that will wear well against the hard anodized piston? Does standard anodize do well against hard anodize, or should I look into a harder finish possibly with a dry lubricant? Thanks in advance for the help!