Treadmaster has consistently been rated the best, or near it, for decades. The downside is that it can be a bit harsh on bare feet; I wouldn't use it for that reason. For non-skid on the top of the varnished
bowsprit I use International's non-skid additive (polymeric spheres) mixed into
varnish for the last layer on the top - it works great and is nearly invisible. Previously I used the 3M tape which also worked very well but hid from view the
leaks under the
varnish (a bit like painting a wooden spar - bad idea); for the
companionway it probably wouldn't be an issue.
Greg