I've been tasked with creating a dynamic 500m x 500m grid table that we can stretch out along the X and Y axis which will position a grid line at every 500m interval. We use these grid tables to accompany topographical maps, these can vary in size so the dynamic table would come in handy and save a lot of time. I have a half decent understanding as to creating blocks and turning them into dynamic blocks, I'm really just struggling to inset the grid lines. I have attached an image of the current table that we use to give context. As you can probably tell, these take quite a while to adjust for out larger sites. 

Any help would be much appreciated. 

Many thanks, champs.

J