Poodlepup, When you or any of us are trying to diagnose diseases, we need to look for multiple symptoms. Red color isn't even a failsafe diagnosis of RRD; some OGRs never show the red color at all when they are sick with it. RRD has symptoms that are sometimes really blatent, but other times are more subtle. An example is when infected leaves have margins that are different from the pattern of uninfected (same cultivar) leaves. Sometimes the leaves shapes change and the symmetry is lost. Stipules may be hugely overgrown- a stipule on a healthy rose may end up with crazy dentitions when the rose is sick.

I responded under your post in the Roses Forum. LMK if you have more questions.

What a beautiful rose! And a beautiful scene! I think it has grown very well for you in three years. I've never grown that variety so don't know its growth habits, but I would just shape it to whatever shape I could see in my mind's eye; as in -- do I want it to follow the trellis or is it okay if it branches out all over? You're right in that roses are very forgiving, but I will say it takes a certain amount of nerve to take off whole long canes that are heading off in a direction not wanted, but I've never regretted removing them in shaping a rose. However, to get expert advice you could pose your question on the GW Rose forum. You'll get lots of responses. Anyway, I would shorten the canes going at right angles. Some roses will produce a lot of little blooming branches on the shortened part and some will try to grow another long cane. In that case when pruning I'd take off the cane back to the main cane. But you won't know until you see how it responds. It looks like you've got plenty of canes tied to the structure so I'd say just shape the wild canes to how you want it to look and see what happens. It won't set it back. The roots that were supporting the cut off cane will support more shapely new growth Maybe you've already looked at the photos on the link below, but if not seeing them might give you some idea of this rose's growth habit. Here is a link that might be useful: Dublin Bay rose on HelpMeFind. It's very popular!

I would wait until next spring. Old roses can sometimes get in a snit when first cut back hard. If you want to take out the old canes, then you can do it in the fall or next spring. By then you will know if it is a wisdom to take the canes out. Probably they may develop a lot of new growth.