I am using a 92mm f/7 apo with Lunt B1200 CaK followed by a PST #1 filter and then an ASI290, mainly for real-time viewing. It looks pretty sharp even without limiting the aperture.
I usually view the disc surface, and I have never noticed extra reflections despite not tilting. In my R2 imager, I thought adding the PST #1 added contrast. Today with my ASI290, I was not sure it added much, but there wasn't much going on. I wonder if the improvement in the R2 was simply placing the brightness at a more optimal point (since the R2 does not have continuous adjustment).
I went to higher gain for prominences, and then a reflection was obvious. A broad haze mostly to the side. I tried tilting it, but it just produced a more focused reflection.
So I was planning on permanently mounting the PST #! somewhere in the Lunt CaK, but now I am not so sure. I'll need to demonstrate a real improvement on the disc.
George