Personally I'd kill for C1 to write XMP files with the C1 adjustments included. Keeping track of the adjustment data for backups is a pain in the neck whereas with ACR/LR the adjustments are always with the files, wherever I move them or whatever I do with them, whether I've used 'sessions' or whatever.
That is the definition of EIP format.
Use EIP format and all adjustments are always with the files where you move them or whatever you do with them.