I would like to recreate an eCommerce website to sell images on different mediums(postal cards, posters, canvas,...) and in predefined sizes for each medium and at a predefined price.

My actual website under Ubercart:
http://www.israelmodernart.com/israeli-painters/dan-groover/light-painti...

Example:

Medium 1 - Postal cards :
- Size 1 - $1
- Size 2 - $2
- Size 3 - $3

Medium 2 - Posters:
- Size 1 - $10
- Size 2 - $20
- Size 3 - $30
- Size 4 - $40

Any Medium
- Any size

I understand that with Drupal Commerce each variation(in my case Medium & Size) should have its own SKU.

In my case most of the time images will be proposed on all the mediums, and in all predefined sizes and at the predefined price for this medium and at this size. But It could be possible that the price could be set differently for some images according to the popularity of the image.

If I'm following the spirit of DC and kickstart 2, I will have to create easily 20 products variations for each images, and will retype over and over the same information of medium/size/price.

I have seen the solution proposed in this question http://www.drupalcommerce.org/questions/3178/best-way-setup-product-grou... which is great, but doesn't handle stock for variation.

Could I have more explanations on this ?

Personally, I would create a single SKU for each painting and each size. Finally, I would group these SKUs by painting.

Is the solution proposed is still the best way to go for my project ?