Start by honing the cylinders a little to eliminate the rust, and inspect all of them with a bright light and a good magnifying glass for other possible cracks. If you don't find any, sleeve that cylinder. Stop-drilling the ends of the crack is probably a good idea, but it's not absolutely necessary. Use a thin sleeve- - - -3/32" wall thickness. That minimizes the amount of material you'll need to remove to install the sleeve. There are also 1/8" wall sleeves available, but those are usually used to repair cylinders with holes in them, not cracks. Leave a small step (about1/8") at the bottom of the cylinder for the repair sleeve to bottom out against- - - - -that traps the sleeve between the block and the cylinder head so it can't move after it's pressed into the block.
Jerry
