Steve’s post about ‘Weak and Strong’ is very informative. However, if you want to ‘stretch’ a family with instance parameters AND a weak ref plane, simply ‘Tab’ until you get Revit to say ‘Shape handle’ and then trigger the stretch. Video and image below:
Thanks for sharing this Luke, it’s really useful. I hadn’t realised you could cycle through the shape handle and reference options. I've been using Revit for number years now and it’s surprising how often you learn something new