You can now copy Available Sizes from one product to all products in the store that match the same aspect ratio.
This 'Bulk Update Other Products With Matching Aspect Ratio' will save you so much time - it will find any other products within the same Store that have the same aspect ratio. It will then copy the Available Sizes from the product you are working on, over to those products, in one swoop!
Note: Once you have selected the sizes you wish to be available for a product, make sure you first click on save. If you do not click on Save prior to clicking on Update All, any changes you might have made will not apply to the rest of the products.