I use 50/34 oval chainrings from ROTOR. Do you know if they fit with standard road chain line? I run 12S Ultegra di2 and if I play with the spacers and extend the chainline, then the FD will not work as setting the H/L limits is very limited. Another point is that I need to move FD relatively high (for equivalent of ra 52T chainring), it is not possible in some cases as the FD mount is not high enough.