@colinmford@behdadesfahbod@cjtype I batch export the kern feature with subtables. Sometimes that's enough. If not, wrap the table in useExtension.
I tried the fontTools.feaLib method, but wasn't able to use it with a goadb file when building.
@behdadesfahbod@cjtype I guess my question is "how do I avoid getting the 'GPOS feature ‘kern’ causes overflow of offset to a subtable' error?"; the solution sounds like it's "use fontTools.feaLib instead of MakeOTF to generate the kern feature"?