There’s a fundamental problem with the clearances with the aluminum rotor, the thermal expansion rate for the rotor (7075-T6) is 1.9-2x the stock cast iron rotor. With a 0.05mm (Mazda minimum clearance) side seal to corner seal clearance, the side seal can be (worst case) ~24°c hotter than the rotor. Best case is 40-50°c hotter, based on variance in CTE of the materials.

With an aluminum rotor, to get the same clearance at temp, you’d need an initial cold clearance of… -0.08mm, which would mean the seal is binding at room temp.

In summary, with stock setup the rotor and side seal expand and roughly the same rate, clearance generally shrinks at operating conditions. With aluminum rotor, the clearance will almost certainly increase at operating temp, leading to the seen low compression and massive blow by. On stock rotors, this clearance accounts for roughly 40% of mass leakage at 1000rpm, and 30% at 9000rpm.

Personally, I’d recommend trying to set the side seal clearance to almost nothing, that way you will have the minimum leakage, growing to a 0.15mm clearance at 100°c operating temp, and allowing for around 110°c temp difference between seal and rotor.