I have done a number of things and I am not done yet.
I work and have worked in a machining atmosphere for a very very long time, so I tend to use a lot of that methodology.
I don't have "T" slots on my machine - the new one will have.
I do cut through and into the sacrificial board, and yes I do screw into it also.
Screwing into the sacrificial holds down the workpiece flat and very securely.
I have used double sided tape also - works great, but gets expensive.
I also use stepped aluminum clamps, which work well with "T" slots.
I also use just strips of scrapwood and blocks and screws - cheap and easy.
I also use a drill press vice, bolted down to my machine bed.
My bed under the sacrificial board is an array of 1/4-20 holes spaced 1" apart.
Lots of people use a vacuum table. Some day I will get there.
For now I screw down to the sacrificial board.
I really don't worry about the sacrificial board - to be it is a consumable item, period.
I can resurface it 4-5 times until it is too thin. It gets to looking pretty interesting by the time I resurface it.
I replace it maybe once a year or so.
I do engrave a grid and some text and use black paint for the grid and text.
I apply a heavy several coats of poly and it is nice and smooth.
I use a hand planer of sorts - visible on my swap project post - to scrape off the raised ares from the screws.
Everything has pro's and con's
Next year at this time I may be doing something entirely different.
This was the New Bedford Tattoo sign. 96" long and 22" wide and 2" thick. I made the bar holddowns with screw handles. I was doing tiled toolpaths and a 16" feed through. You can see my machine bed with the threaded holes. I used those holes for the threaded clamps. On the start end you can see how I sometimes use a piece of scrapwood as a holddown. I did the outside profile cutout also but left a 1/8 onion skin. The HDU cuts so easy I just cut the onion skin with a utility knife.
You could build dedicated fixture plates also, with Destaco clamps, mity bites, cam locks, etc. Look at Jergens, Fixture Pro, Carr-Lane for ideas in fixtures and clamping solutions. McMaster also carries a lot of fixture parts.
There is no one way that is better than another. Only the way that works best for you.
To me - work holdown is kinda application driven. I figure it out when I get there. I don't always do the same thing.