Numbers such as .029 and .019 are referring to the diameter
of the fiber optics being used. The larger the number...the
larger the diameter.

I have a Spot-Hogg and use the .029 diameter for my 20 &
30 yard pins. At 40, 50 and 60 I use the .019. I like the
smaller diameter on my longer ranges as it does not cover
up as much of the target.

There are some great new and improved sights on the market
these days. I think you'd be doing yourself a big favor
in 'upgrading' to one of the newer models.

TB