[R] glm - poisson

[Oli]

Hello,

I have a question on glm - poisson. I would like to
fit a model on proportion of counts with some factors,
and I decided to use glm - poisson because count data
is essentially related to poisson. However, since I
need to deal with proportion, and glm - poisson does
not allow non-integer responses, I am thinking of
adding an offset term = log(total). Is it the right
approach to it? or should I use quasi-poisson family,
or should I even use weights?

Thanks for your help!