I don't see why the 18-110 wouldn't work in crop mode.
J Brown , Can you tell us what your settings were for matching the FS5 to the FS7?
I ended up with setting gamma to Cine 4 and color mode to Pro to match my FS5 to my FS7 with Slog3 and the 709a LUT. And I lower detail to -7 on the FS5.