My preference is back to front although others will disagree. ;) Check out some books, find a system that you feel will work 'best' for you, then get proficient at it. As you learn more and become experienced you can make changes to make it go better.
I have a number of video clips on You Tube. My user name is lauraannfry1
No, the turn buckle (I may not be using the right word for it) is the gizmo with the wing nut at one end. You can turn the buckle part to shorten the length/distance between the two s hooks which will apply more tension to the brake band so the warp doesn't slip
But if you have so much tension your shuttle won't pass through the shed, perhaps you have too much tension on your warp?