Sam, it depends on your winter conditions. Do you know your USDA winter hardiness zone? If your winters are cold, pruning now, while the roses are showing new growth, may promote new growth, which is very tender and subject to cold damage. Waiting until after a good hard freeze would be much better. If you winters are mild, which I suspect from the height of your plants, you can go ahead and shorten the roses a bit now. In my part of Zone 8-9, we prune between Thanksgiving and Valentine's Day. That may work for you, too. Remember that climbing roses are not supposed to be cut back hard. Their pruning is more selective.