"When a man with a .45 meets a man with a rifle, the man with a pistol is a dead man."
- Ramon Rojo, "A Fistful of Dollars"
Ramon might have been a wee bit mistaken, being that the man with the .45 was Joe aka The Man With No Name. But for miniatures and monster manuals, I feel like the monster manuals are the man with the pistol and no clever tactic for dealing with the rifle.
When the miniature I plunk down on the table the monster manual description clash, the miniature wins.
A picture is worth a thousand words and a three-dimensional sculpture plunked down in front of your players is worth any ten pictures.
I find my players are willing to forgive minor differences - "all of these skeletons have cleaver-like swords instead of the axes and scimitars on the minis." They accept that somethings I want orcs with crossbows but I don't have an unlimited budget to go buy orcs with crossbows. Whenever possible, I try to match up descriptions and equipment and all of that with my minis but it's not always possible.
But not bigger, morphological differences, like "this minotaur is actually much smaller than this" or "this giant worm doesn't have teeth like the mini does" or "this grey dude with an axe is actually a blue dude with twin scimitars." It seems to undercut the suspension of belief too much. I'm much better off putting down a generic counter.
As a result, I spend a fair amount of time converting minis to GURPS, rather than the monsters the minis are meant to represent into GURPS. I'd rather match the sculpture than the book, for the impact of saying "this is exactly what you see. Give me an initiative roll. I recommend rolling high."