This is where you can get creative. I think a BBM cam gear has 50 teeth? If so, that's 7.2 deg/tooth. So you can play the games of moving the chain 1 tooth in either direction in combination with using the different key slots. I've done that many times to get it "where I want it." You clearly know how to degree the cam so go experiment and see what you can come up with. You can do this!
Even if You were to advance the cam sprocket 1 tooth, that's 14.4° at the crank, then use the 4° retard position (8°@ the crank), that's still 6.4° advanced from the initial reading of 107.5-108°.....101.1-101.6° advanced.