KenV, you need to stop digging. Nobody 'stretched' the A330 to produce the A330-300 as it was that shape at launch. From memory the MTOW at launch was 210 tonnes and increased to 212 tonnes during the first production run, with one engine variant with a lowly 184 tonnes MTOW. The MTOW continued to grow and these days is 242 tonnes on the -300 and -200, with the latest versions at 251 tonnes. The fuel capacity differs by customer and market, with the MRTT variant making use of all the tank options. The lowest fuel capacity is on the A330-300 'Regional' jet and the highest capacities are available on both the -300, -200 and the most recent variants.
As an aside, it is pretty rare for MTOW of a design not to increase during service and development. I've no idea why you throw information around on a topic that you have little practical knowledge of.
If anyone feels the need to correct my memory of the weight history please do so as my grey matter is always strained.
Tank fits and volumes:
