I don't think you won't succeed finding them but it will take a lot longer. Fortunately although somethimes they aren't there, as you approach they get bigger, it took a lot of free roam cycling to find them, then I had to keep a record because I kept forgetting. The forum cheats are mainly to improve speed I would say but everything else is there so don't look if you want to do it alone. Keep an eye on the map in the centre of your manual or download one so you can make it larger.