Cokin filter size for m4/3

I'm looking at probably getting a set of SRB square filters (same size as cokin) for my m4/3 kit but am unsure as to which size to get.

The A size will fit filter threads up to 62mm which AFAIK exceeds the size of any current or planned m4/3 lens. Am I likely to get any problems with the holder showing up on the size of them lens if I get the A size.

The other option is obviously the P size but I think that only goes down to 48mm, so I geuss I'll have to use stepping rings if I want to be able to use that on all the m4/3 lenses.

I was thinking about getting the bigger incase I have the thought of changing systems but I doubt that will happen now it looks like there is a weatherproof camera on the horizon (as long as it turns out ok).

I'm leaning towards the A type but the main thing I'm worried about is vignetting/the filter holder showing up with wide angle lenses. Anyone have any experience with this?