Type III clematis, which Polish Spirit is, are genetically programmed to bloom at a certain point. In my garden, I have never tried to limit a clematis' eventual height by pinching out growing tips. It would be worth a try to see what happens. What I find interesting is that the plants tend to bloom with their blooms facing east. In my garden, the plants tend to follow the sun and the blooms are more on the westerly side of the trellises than on the easterly side of the trellis. This of course assumes that the westerly side is not blocked to the light by the garage itself.

I have a similar problem with Ramona grown up an east facing fence, she spills down the back side and the neighbors see most of the blooms. I've cut her back hard and pinched but still she grows to the top and spills over towards the sun.

BorS, do the blooms on your Ramona face the west or east? Can't quite figure that out by your post.