I don't think clamping should be the primary concern of bench design. Proper height, stability and flexibility are more important.
So long as the top is sturdy, boring the occasional hole to accept holdfasts will accomplish most tasks.
*The more things I make, the less I tend to clamp them down, particularly when planing.*
It is VERY rare that I hold a thinner piece of stock upright in my tail vise. This position duplicates the function of the (more versatile) leg vise.
The movable tail vise on my bench is frequently jammed due to Seasonal movement. I did not build the bench and would not include the feature, as it offers little utility and is difficult to make. Your all wooden design would be more sensitive to changes in humidity.
An alternative exists - which would be simpler to mount.
https://store.woodandshop.com/produc...ian-workbench/