not very.

Against the odds, I have come to love this rose. I confess to being a reluctant owner - those frilly blooms, those shiny leaves and it is rather too vigorous for its allocated spot on the allotment. However, it is one of the last roses to come into flower and, because it has been largely ignored, it tends to hang in great cluttered swathes of scented blossom, waving around like an unruly teenager.....which is why it is a good job it is not terribly well armed since I have to sidle past (under) it every time I cross from the fruit to the veggie area.....which is numerous times a day. It (ahem) grows on the remains of old tomato supports - pieces of unmatched timber which tend to litter the whole plot, so it sort of spreads around at shoulder height - I continually tuck wayward canes behind each other (making future pruning nightmarish to consider), especially since it is not particularly stiff.....but entirely lacks the flex of wichurana ramblers, for example. It is currently on collision course with a helenae hybrid (they are less spaced than your, Kips, at around 20 feet) so I squeeze sweet peas or french beans or mange-tout or other annual things in between them. It is one of the healthiest roses in my small collection although I am debating whether to remove it to the woods. I think, a more supported specimen than mine would be a great addition, especially for a fragrant display which would probably synchronise rather well with your musk rose.....and I love the tiny pink buds which open to cupped bowls of petals. It would very likely stay green all year for you, Kips, whether you consider that problematic or not, I dunno, but it is a refined and forgiving addition to my hurly-burly chaos (I have white paeonies, tulips, and a smaller HM, Jacqueline Humery, frothing underneath its arching sway.
It will easily stretch to 15 feet, even in chilly UK conditions. Might be a giant for you.

A lovely rose.

Thank you for your reply Camps!

I had a "hole" saved in a bed (was bigger before this fine idea came to me) Something to soften this area is needed I could pillar her and let a few canes spread the seating area direction too. Or maybe I should just try a Bolero for some white blooms to cut....hmmm

I had to go out and look at mine. I'd say one prickle per foot of cane, on average, so as Camp said, "not very".

Look at 'Snowbird' as well, a new favorite. Nice rose!