If you are looking for sheets apropriate for printing on A4 or letter, this is it.
The sheets availible in the "4x10" and "4x12" directories will fit on both A4 and Letter sized papers, though 4x10 on A4 will only work if your printer is capable of printing to the very edge of the paper.
Using the 4x10 version will save you some paper, but 4x12 is only be 8 more sheets, and will simplify things a lot if you, like me, are going to glue the map on 3 large sheets of cardstock. 
In the rare case you are using B5 paper, the 4x12 will fit perfectly, 4x10 won't.