They could vary from manufacturer to manufacturer slightly. So may not have a 'standard'.

Are these nib walls coming up from the floor or coming out from the wall? Are they merely side panels of the cabinetry, or structural?

just realised that my suggestion has overlapped with Dr Retro and i agree that you should be able to have (from left to right) a 900 wall cabinet with three equal doors, a 900 wall cabinet with the 900 wide rangehood and three equal doors and a 600 wide wall cabinet with three equal doors ie 8 x 300 wide doors with the left hand side of the range hood wall cabinets lined up with the 900 corner cabinet BUT is there any special reason why the wall cabinet for the rangehood was suggested as 1000 wide?? if so, the same concept applies ie left hand wall cabinet would be 850 wide with three equal doors, 1000 wide range hood cabinet with three equal doors, right hand cabinet 550 wide with two equal doors..ie 5 doors about 270 wide and 3 doors about 330 wide above the rangehood but aim for the 8 x 300 doors.. the cabinet maker should allow for all the necessary clearances and fillers to create a uniform appearance

Hi Loraine, Lift up mechanisms can be used on the cabinet widths indicated in your drawings. There are regulations to clerances around gas cooktops (as you know from a previous post) including heights. According to the AS/NZS 5601.1 clearance rate of no less than 600mm for a rangehood taken from the highest part of the highest burner of the gas-cooking appliance (but I recommend 700mm high clearance from the benchtop ergonomically). As for width, personally I would not recommend using a 600mm wide hood over a 750mm cooktop and 900mm is your best option as this provides better catchment area. If you opt for an Undermount, say something like a Falmec, these can provide 1140 cubic mts of extraction an hour compared to older slide-out-hoods that only provide 300 cm/h where this newer type is far more efficient at helping keep your new kitchen clean and fresh. You can easilly achieve this 900mm by taking 50mm off the left and right overheads without disturbing the balance of your design. Hope this is of help. Regards Malcolm