Is there any reason to not use 3/16 brake lines coming out of both MC ports? Tighter bend will give an inch more side clearance to transmission, and the SM420 weighs 42,000 lbs so removal even with a cherry picker one wrong sway could damage stuff. Clearance space is good.

Originally there's a 1/4 line going across bellhousing crossmember to passenger side (RF and both rear brakes), so I'd prefer 1/4 if I had my druthers but space is critical.
FYI, picture shows MC to rear trans support crossmember clearance with the Performance Online setup.