I think it's easier to just use a huge tiledbackgroundlayer rather than tiles as Construct just isn't really usable for large tiled games. As an example, level 1 of my game was originally meant to be 205x57 tiles of 32x32 each, totalling 11685 tiles. Instead, I use a tiledbackgroundlayer of 6560x1824 px. Even with sprites of 64x116, it still only uses approx 66MB VRAM.