How to route and solder TO-263AB packages?
Yes the sizes are standard. Any major manufacturer will use JEDEC standard dimensions. There can be minor variations within the limits from manufacturer to manufacturer because their tooling will vary. 
Aside from making the traces leading away from all the pads heavy enough (width and thickness) for the current, the most important thing is to ensure you have low enough thermal resistance for your application. Most of the heat dissipated by the part needs to be conducted out from the tab. This is not a simple calculation- it depends a lot on the type of PCB, whether you incorporate thermal vias under the tab and so on. This TI application note has a lot of information- far too much for an answer here. Keep in mind that datasheet \$R_{θJA}\$ numbers are based on assumptions for the PCB pattern and construction that may not match what you come up with. Usually they're in some other document than the datasheet, if you can find them at all.
The solder paste stencil "hole" for the tab is so large that it requires a grid pattern of support but the stencil manufacturer should do that for you automatically even if you just create a rectangle of paste. 
As far as the exact pattern, IPC has guidelines as to the pad dimensions but the full standards are not free. If you find a suggested PCB pattern on a datasheet that fits, it's probably good enough. Some EDA packages such as Altium will help you create a new IPC-compliant pattern based on the exact package dimensions and tolerances. 


Below is a rough guide for coupling to the PCB (only, not to the ambient), from this app note. Note that it's assuming 2oz copper.