Here is clematis #2, same trellis, same issue. In full sun but with the trellis, it gets quite a bit of shade.

The problem won't be the shade but Roguuchi doesn't climb and Clematis can't climb wooden slats like that. They need something round no bigger than a pencil. You will need clips or ties.

Oh, I was planning on tying it up. I read that it's not a traditional climber, more of a 'clamberer', but can be tied/trained up.

You could always remove some of the vertical slats until it gets bigger, then put them back. I've never put an obelisk right over my clematis. I've always put it next to it and then trained it onto it.