Shape them how you want to. These are pretty hardy I hear. I have some I just planted in the fall so I'm excited to see what they do. If it were any other type, I'd wait awhile longer, personally, I don't remove any mulch until towards the end of May, had many cold snaps that has taken some of mine out prior- so I've learned.
You can shape them however you like and to the desired height- might slow bloom time, but they'll bounce back quickly I'm sure.
Good luck.

Thanks primgal36. I guess I'll shorten the highest stems. Now, how do I prune them? I have read about pruning, but I think I need a visual guide. Any links?

elleni, it's pretty basic. Here's what you do. Cut back any parts that are brown and hollow, you will know. If it's green and fleshy, it's good. This will only revitalize and stimulate growth. You really can't hurt them.
There are many books you cna get at Half-Price books, or go to the library or the Horticultural Society has an extensive library. You can also go to the garden centers, they often have free handouts, or free classes. Noble is excellent.
If you like roses, get more of them, they really aren't that hard to care for. I use Bayer 3-1 for roses. I apply it 3 times during the season and it works pretty well. Also if you can ,don't water them overhead, but if you do, do it early in the morning so the leaves have time to dry out with the sun.
Wear gloves when you prune, I've heard k/o's thorns are pretty wicked.
I wish you lots of luck this season, hopefully I didn't throw too much at you, but don't stress to much, plants are forgiving.
Have a good day.

elleni,

Best way to know exactly what is dead? Wait a couple more weeks! I have many rose bushes - the best way I have found to decide where and what to cut is to wait until they have leaf buds on them and cut off anything beyond those - it'll be dead. Then, it's a matter of shaping to what you like. "Knock out" tends to be kind of a pillar rose - long whippy stems that kind of waterfall - make sure you cut just above bud unions at a slight diagonal and it should start to bush out more.

Best gloves? More expensive - but the best rose gloves are real kidskin at least on the palms. Rose thorns'll go through regular leather and any cloth. I hear that "Foxgloves" work too, but I haven't tried those. I use GardensAlive! rose food for mine, though I seem to have a wonderful compromise with the wildlife in winter. I let the bunnies and snowshoe hares trim the bottoms of the bushes and they leave me - well - the bottoms of the bushes in one of the best forms of fertilizer there is: bunny poo! :)

-Marie