I can answer your questions. the two lines are for max and min brace height, anywhere between the two is ok. Some new strings sit way above the high mark [closest to trigger] not to worry they will stretch in. I set my FFF strings a good 3/8" above the high mark as they really stretch alot. The lowest brace height gives a few fps more, but is harder on your serving as the string tends to bounce off the riser when you shoot it like that. The Excal pro's from Dover claim that the sweet spot for most Excals is w/ brace height at around 1 1/8" to 1 1/4", which is measured w/ ruler from end of rail, translation: about 3/16" below high mark. The hooks on rope cocker are some kinda tough synthetic material w/ brass pulleys inside them. If you are handy, you can find a drill bit just a few thousandths of an inch bigger than the slot in them and kinda hone them out a tad and radius the edges some. Makes it fall of the string easier after you cock it and ensures there are no abrupt edges on hooks to wear your center serving. Emaxes are real hard on servings. Use very little wax on them, try and find "Boo" on Excal forum, aka "Dnk" on HNI and get a string or two from him, his serving life is easy double factory serving life. FWIW: I found the stock Excal 357 gr arrows and FFF string loud, brutal and way more than I wanted in an xbow, so I use 431 gr GT's from Danny Miller, great b-head accuracy w/ 100 gr Slick tricks.