Lanefan
Victoria Rules
We put our own grid on a chalkboard using indelible-ink felt pens*. Half an afternoon's work that you only have to do once, 'cause it lasts for a lifetime. 2-inch grid, 10' squares, works like a hot damn.Interesting - I don't think I've seen a 2" grid!
Back in the Day here in UK Games Workshop put 28mm metal minis on 2 cm square bases, so you could almost have got 3 across a 2"/5cm corridor. But GW's own dungeon floorplans used a 2 cm = 5' scale so too narrow.
Then during play, when it's needed either I draw the map on the board (using chalk, of course) or the players do from my description.
* - a simple ballpoint pen works too, but it doesn't have the same staying power and eventually needs to be re-done.