Vancouver is a city on the north bank of the Columbia River in the U.S. state of Washington and the county seat of Clark County.
The width of the twin quilt is 66 +12 (for the two extra columns of 9 patches) + 4 (for the two extra strips of sashing) =82, which is a bit wider than your target of 78, but close enough. Plus, it's nice to have it a bit too large than a bit too small.
King size cotton patchwork quilts are available in different measurements. While the regular king size quilts measure 90 x 100, oversize king quilts are 95 x 105. California King Size cotton patchwork quilts are the biggest of all and they measure 120 x 110. Depending on the size of your mattress, you can get the right measure for your cotton patchwork quilts. High-quality cotton patchwork quilts are now available in online stores.