I have a few thoughts:
One is... what a great GUY! AND… Congratulations!
The arbor is beautiful and roses will love it but...I do have a concern with passing through and possibly hurting ones self or snapping branches.
I know of at least two that was placed in a walkway and when passed stems get broken and people get “thorned”. I don’t want to be a kill joy in any way or bust your bubble, I am just explaining how I have seen it to work.
Now, if you do not use that walkway and entrance, never carry groceries or children or stuff thru there and don’t plan on using the hand rail; it would be fine, again the arbor is beautiful, no doubt!
And I wish I could afford one! But I wouldn’t put it there for roses .
Clematis yes, roses no.
I just went to big lots and bought bamboo sticks to make my trellis’.
You are blessed.
It may work if you planted the roses far enough away from the center of the arbor on the left side (of the photo) and carefully monitored the growth and tied every 6inches or so. It sounds easy enough but to actually keep up with the growth will be a mindful chore in and of itself. but...that may work.
Don't mean to be difficult.
May I suggest walking through it several times with something in your arms ,walk naturally and see if you hit the arbor. It may be wider then the ones I know of .
My back porch steps are only 3feet wide.
Enjoy and again congratulations.
Swindy, a well bred Climbing Blaze; within a good 3years I'm guessing.