Sale prices in the variations?

Hello!
I have a couple questions about variations and how to use them correctly.

I have a shop with multiple sizes of the same lotion.
Right now, I have it set up where the different sizes are reflected in the variation control area. I have each size (1 gallon, 8 oz, etc) at its own price and weight.

My first question is:
If this lotion goes on sale, how can the sale price be reflected in the variations? When you regularly add a product, there is a section to add a sale price. But there is not an option for that if it is part of the variation, just one space to enter in the sale.

Second question:
I notice that the grid listing reflects the highest price of the item, even if a lower price is listed for a smaller size.
Is there a way to make the lower price the default?
Or in the grid view, how can I express to my customers that the price they see is just for one of the sizes?

Thanks so much!! Any help is appreciated!