I added a cover to my vent yesterday. It went well and I thought I did a good job. Then I noticed the "non" prefix on the tube of Dicor that I thought was self-leveling.
Pictures are below. I squirted Dicor into the screw hole before attaching the bracket, filled under the bracket before tightening the screw, then covered the bracket in the area where I had to cut away the old Dicor to do the install. Should this suffice?
The new Dicor is rough on one side because the excess stuck to the vent cover when I removed it. It's ugly but still well-sealed.
Is there any reason to re-do this with self-leveling? If so, I can't, until this is fully cured. Then I'll remove it later and do it again. If I must, I'll wait until the replacement is cured before reattaching the cover, so that doesn't stick, too.
Edit: the height of the vent itself seems exaggerated by the angle of the pictures.