i would guess the rounded swingarm is the reason for the dual injector, i think a better solution would be a suitable sized u clamp for fixing it on. wont look to pretty though.
fit the rez anywhere you like and the more upright the better. attaching it to the left hand side radiator hose would be a good idea as it would keep the oil warm and have easy access for filling. it would also be a short run to the vacuum.
i put a touring rez on my K7 behind the numberplate. only fill it one a year
