I fit a pair of GC3 L , grip shift model Ergons on my Brommy M, it was a snap.
No grip Mods needed.
the longer Bar ends interfere with the fold, of the HB mast,
to the catch [by an inch] But..
with a loosening of the bolts that secure the grip/bar-end to the bar ,
they can be rotated out of the way. to still fold as before..