I am a newbie to digital photography and i was wondering if it is worth the money and effort to put the following on my Olympus C4000z

1) CLA-1 adapter for filters
2) ND filters ND4 and ND8
3) Grad ND filter ND4
4) Cir Polarizer

I search through lots of web pages and realised that i will need to step up the CLA-1 43mm to at least 49mm for the filters that i want. Even to 52mm...

I am concerned about a few things...

1) Is the grad ND transition line going to match with the 43mm to 49/52mm step up?
2) Will there be vignetting effects due to the step up?
3) How effective will the Cir Polarizer be?

I really appreciate any opinion and advice! Thanks!