John Kuthe wrote:

> On Wednesday, December 2, 2020 at 11:48:06 AM UTC-6, Cindy Hamilton
> wrote:
> > On Wednesday, December 2, 2020 at 10:54:41 AM UTC-5, Sheldon wrote:
> ...
> > > What is 'almost' 1/2" plywood, do you mean some specialty
> > > thickness like 7/16"?
> > Half-inch plywood is 15/32".
> >
> > Cindy Hamilton
>
> And that's almost 1/2 inch! 16/32" = 1/2 inch!
>
>
> John Kuthe...

Yup. It is. Forget the others, if you give a good dimension, I can
tell you (without messing with you like so many do) how to do this
simple.

You are right that a center riser of the wood you said is about right.

Sadly some want you to hire a professional for this simple but
satisfying home job, then positively put you on a rack and try to make
you cry because they watched you spend money.

I have a better idea. Work with what fits you and the budget and trust
yourself on this one. At the worst, you may have needed 24 inch rails
there.