I'm teaching a stacking class in Atlanta this Sept., I have lots of new ideas, if your around, come to it. I'll show lots of metal and metal but also wood and metal.
In the meantime, if you can keep the feet all on the same level, setting one style inside another, that works the easiest. One of my favorite combinations is the 87 inside a 58 set on the lip of the 86. It’s held together with an omni hanger put into the channel backwards. If you chose a profile that has a slight foot, you can set anything on the foot and again, the omni hanger placed backwards will hold them together. I love the elements stacked two or three deep with just the omni hanger. It’s a really nice way to get a very wide moulding. Metal finishes are so good in most interiors now.
I’m going to show a flat backed square profile like a 97 cut backwards to use as a spacer. The back would be on the inside instead of the outside. The outside would be against the rabbet of the shadow box moulding. The hardware fits it in the usual way and it makes nice spacers. An Elements would look really good in a large shadow box and would help give the box stability.
To stack the 117, unless you can come up with a custom made hardware to hold them together, a hole can be drilled in the side of the inside 117 and hang the outside 117 off a screw you put in the hole. Assemble the inside one with the screws in the right place and assemble the second one around it. I’ve done several of these with profile 71 and they come out very well. (I used to come up with custom made hardware for stacking but Tim Dykstra showed me the screw idea and it makes life very easy.)
This is as clear as mud I’m sure. Trying to describe something in a few words is not easy. I need my hands to wave around a bit to help with the description. The main point is to play and see how the combinations go together. There are dozens and dozens that give a distinctive look, for a good price and yet are easy to assemble.