One of the simplest ways around the "draping" problem is a lighter tip and heavier fly. As we all find out when we transition from nymphing technique to swinging, we don't want a sag in the tip sweeping lower than the fly.
Though it's not a popular solution, a long mono leader with BB shot, hung off of a fat belly, can be steered through slots and around boulders. It's swinging a fly using a nymphing rig (but no bobber). It's a method that's worked for me when I've been fishing waters like the Catt where one pool may be great swing water but the next one around the bend may not be. The shot can be added or removed to adjust for depth and current. I still use spey casts with this rig and still swing flies, but I'm using the shot to provide an almost 90 degree hinge from belly to fly that lets me steer it down the productive water.
Also giving some thought to splicing some leftover tips and sinking line so that there's some T-14 or T-8 stuck on the end of some T-3, to try and get the same result.