I tend to wrap the string around one of the limbs be it a recurve or a td longbow.

For the brace height, the cresting pattern is the ticket! Even if you dont have a band exactly their, having one close is a good reference. You can do this easily enough with a practice arrow in your quiver/small game arrow, or one of your broadheaded arrows. Just be aware different string materials will stretch and/or creep to different amounts. Once it settles in (one of the newer materials) on a brace heigth and very little to no more movement is happening, I noticed a bh change after unstringing and letting it set for awhile.

Normally on my backpack hunts I do however just carry a bowsquare or my partners (mostly compounders) will carry one. For weight you can cut it say 1/2" over your bh marking or right on. Its also nice to have for marking a string to measure things when you do get lucky. On that note, a marked string will work perfectly. So many options......