Cool. Please report back on your findings. It's those moveable furnishings that will eventually add-up to cause problems starting on lower machines. At some point it's a matter of --- wouldn't be a problem for the map to grow in square feet but-for the fact it makes so many more rooms to furnish. To the extent you can use JPEG furnishings, that's better for this.. the more PNG furnishings (using transparency), that's going to eat up resources many-times worse than the JPG's. To the extent you can burn the furnishings into the background map and not have them moveable (in a graphics program / ahead of roll20), that's going to save you overhead too. Dynamic light is another one that's going to use a bit of graphics display resources. Theoretically if you don't use Dynamic light, that might allow you to go 'even larger' on the map, though I doubt this will be the limiting factor if you reach some ceiling. Still, the question remains, how large! Note that Roll20 has a feature where it recalculates and loads only 'the section of the map that a player is zoomed into looking at'. That's not a perfect description of the feature, but basically Roll20 automatically sub-divides your large map, and makes up littler sub-sections of the map to load when you're zoomed in. And also I believe it makes a lower resolution version of the overall huge map, for when people are zoomed way out and viewing the whole map but in low detail. Roll20 actually added this feature about a year ago, and much larger maps have been more useable since then.
