DIY Deck Stripper Formula
I found my answer - pasted below for completeness.


Short answer is 2+ oz to 1 gal.


Homespun Paint Stripper
Mixing your own.

By The OHJ Technical Staff
Old House Journal

Well before today's sea of commercial chemical- and solvent-based paint removers flooded the market, folks set on stripping mixed up their own. This caustic-type stripper is concocted to taste from common ingredients that cost next-to-nothing.

1lb household lye (caustic soda)
2 or more boxes grocery corn starch


In a non-metallic container, such as a joint-compound bucket, gradually dissolve lye in 2 gallons of warm water. Start with a medium-strength solution Ñ say 2oz. lye per gallon of water. Test for effectiveness, then increase concentration if desired. Make a pasty stripper by mixing corn starch and water in another bucket. When the water is milky, slowly blend it into the lye solution. 

Apply with a tampico-bristle (whitewash) brush; the stripper is particularly practical for removing paint on masonry. However, like all caustic strippers, this mix is highly basic and will darken some hardwoods. Test first in an inconspicuous area and rinse the surface thoroughly before repainting. Most important, work carefully while mixing and applying the stripper. Wear eye protection and rubber gloves, making sure to rinse skin immediately if it comes in contact with stripper. 

Edit:  I attempted mixing this as strong as 1 lb Lye: 1 gal water and letting it sit for more than 3 hours (while reapplying frequently)  Still no luck on my deck.  Back to finding a commercial solution