They hold the normal weight of a roller shade.
Yes, "can hold a shade up to 30lbs, at a maximum width of 80" is stated specs.
Universal. Shades with a pin on one end and a tab on the other fit fine. And have lasted over a year without a single issue.
You will be fine using these brackets. Your shades are 72" and the max width for these is 80". As long you realize that your shades weigh 30 LBS or less then your all good to go. David
Assuming that the inside of the window frame is clean and any paint is sound and not peeling, these mounts should be more than strong enough for any normal use.