A normal Shinju harness can be used for suspension (if tied carefully) in most positions: face up, face down, side. This harness is used in exactly the same way, but I find often provides better comfort when suspending. This is the chest tie I recommend using (in combination with a hip harness) when first learning to suspend.

It's fairly common when tying this to discover upon tensioning the second set of shoulder ropes that the original shoulder lines become too lose; you may need to tie the first set of shoulder lines a little tighter than feels normal in order to get even tension at the end.

Be careful that you don't go too low with the chest wraps, particularly when tying on someone without breasts to act as an anchor and reference point. For most people, the most comfortable positioning is with the upper wraps almost as high as you can get them, and the lower wraps just a few fingers below the nipples. The lower you go on the ribcage, the weaker the ribs are, the more you restrict breathing, and the less leverage you have for controlling the orientation of the torso relative to the hips.

There's also an alternate way of weaving the 2nd shoulder rope in the front, where you don't go down to the lower wraps the 2nd time; it doesn't load the shoulders quite as evenly, but may be more comfortable on the sternum. See this photo for reference.