Thanks for the reference there MagitekElite
I've seen no problems with lag because of long tilesets and .png images are really small in terms of file size. Even using one that's 256 x 44096 it's only 3.37 MB, however if you go for a tileset like this then you're still limited to seven autotiles.
So really I'd include what you need or want for a map and don't merge sets with things you don't need on the same map, I've got three standard grids within the templates and grids gallery which MagitekElite mentioned:http://www.rpgrevolution.com/forums/index....m&album=154
You can use them for copying and pasting certain individual tiles over if there's only a few you need.