Screwup after screwup... what to do?

If you bought those headman shorties you should not need to disconnect any steering linkage. I went with the cheap long headers and that took me 3 very leisurely days, that is also including installing manual steering and fabbing an idler pulley for the engine. I think with the shorties it will be a piece of cake to get them on. down pipes could be a slight pain i suppose, but you can use jerry6's as reference.