CAT C for final approach has NOTHING to do with weight, flaps
Aircraft category is based on max landing weight VAT and is for STRAIGHT IN ONLY!.
For JAA,it doesnt change depending on flaps,speed changes ....
For FAA,if your speed will be above 140 for example,(flaps up,asymetry)the pilot can increase his minima to CAT D.Flaps do matter for your final approach speed..even pilots with lack of experience know that.
Aircraft circling category is dependent on a MaX IAS used during the maneuver(yes directly dependent of flaps setting),and depending on the max IAS category you fall into before the maneuver,a specific obstacle radius from the runway must be observed.
1.3 times Vref A380 or DH8
An A380 in JAA may fall in C category.(so huuuuuge flap)
So for planning purposes,the minima for RVR and DA/MDA will be based on CAT C.
If they perform a flapless landing,the cat will remain CAT C!
In FAA lalaland,they may increase their DA to cat D.
Same for Dash 8, maybe cat B.
Such are JAA regs !