1
Once you adjust the data to only include seasons with games played less than 140:
Since 1980 there are 34 4+ WAR C seasons and 26 4+ WAR 1B seasons.
So there are actually MORE quality Cs when PT is limited per season in the current era. Basically, C limits elite players because you don't get ENOUGH of them.
The option of DH should fix that for Montero. The ideal jobshare with Montero may be something like 65 C/ 35 DH. That way you keep his bat in the everyday lineup, keep him fresh, and gain the massive position value at C.