How to get user window.weight or repeater's row number

Hey there,
I run a Real Estate Agency and I’ve made a website using repeaters to show all the properties.
In the home page I made smaller ads using repeaters, stretched to the page.
Now I’d like to add more content to the home page and a smaller number of ads.
Actually I calculated 12 ads per category because most PC’s resolutions will have 3 ads per row, while some will have 4 ads per row, and tablets 2 ads per row, so to have all complete rows of ads without empty space the least common multiple is 12.
Now to reduce some space I’d like to add a max of 2 rows per category.
Is it possible to get a repeater’s row number based on user window.weight or at least calculate user window.weight with velo?