I bet this marker-board draft board was a work in progress from what really was the real draft board on the final days ...
The real physical draft board was/is a huge magnetic or corkboard deal where each player has a little piece, and you can pull this players' piece off as they are chosen, as shown the last few years in video taken the day of the draft last April by CBS 11, local station here. (I just looked at the old video of this "real" draft board so I'll try to interpolate, wish I was better with computers so I could post a screenshot here .... you can't make out any player's name unfortunately, just the overall scheme of the board) ...
That draft board appeared to be all positions laid out across the board in rows that represent 1st round at top, FAs at bottom. I think this because there were only seven (maybe eight) rows on the board, representing the seven rounds, maybe FAs as the bottom row. ... Then I'm thinking within these rows representing round-value, players little pieces are ranked/staged at each position, for guys that are value just in that particular round.
To explain again: The first row I'm guessing represents first-round value guys, with who is ranked as the better first-round talent at that position ranked at the top of that row, then other first-round talents at that position underneath him. Underneath this is a second row representing the second round, position by position across the board, with second-round value guys' names underneath it, the better guys higher up under that "row." And so on down to FA. When you pull off a guy's name, it reveals a blank square.
I'm pretty sure of this, because almost all the guys' names at the top of the board had been pulled off under their position, and (this was in the fourth round when the video was taken) there were a lot of guys left in the middle of the board, but nearly everybody at the bottom was still left.
There were some names that were "blank" near the bottom of the board (magnetic names were pulled off revealing a blank square), which had to be guys that other teams had picked as "reaches" according to the Cowboys.
I hope I made sense here?
Importantly, it doesn't look like there is any thought to: "This second round RB talent is a better overall second-round talent than this WR" (say by some complicated points system regardless of position) ... it's just: who is the best guy, say at WR, who is left in the second round (a guy who we feel is a second-round value that is)... Names are stacked up under that position heading for that particular round ... so this guy is a third round talent, the guy under him is also a third-round talent at that position etc. and so on ...
I just wanted to put in my interpretation ... my point is, it looks for sure like the war room isn't looking at a pure 1-300 talent board regardless of position ... They have the first round-worthy guys at the top, if they are first-round talents ... then the same with second round, and so on ...
Pardon my overexplanation ...