3 MTL FL's and some DL FL's??? Cool.
I have the 2x2mm AF insert in my MTL FL. It's a nice airy MTL and a pretty restricted RDL. The 2x2mm insert provides a total of 2.83mm AF. That's the largest AF insert for the MTL FL.
The triple-hole inserts are much tighter. The 3x0.8mm has an AF of 1.38mm. And the 3x0.6mm has an AF of 1.04mm. Tight. Believe it or not, there is a
FT math page explaining how to figure out total AF.
I may have missed it, sorry if I did, but did you try the 2x1.5mm insert? That would be 2.12mm AF. I tried that one last and thought it was a real nice smooth MTL.