Have you ever had difficulty viewing cones while firing?
Several years ago, I saw a suggestion in Ceramics Monthly about
painting iron oxide "stripes" on each cone before firing. It makes the
cones stand out when the kiln is red hot.
These "stripes" remain throughout the entire firing. I mix red iron oxide
with water and paint the lines on. See photo:
wearing bifocal contacts
(one for distance, one for
closeup) does not work.
I always wear glasses when
firing, and put welder's
goggles over the glasses.